I connected it to the office network with 2 SSD WD red. Awesome. Browsing and opening files is just as fast as if I had all the files on my PC's SSD. (I also added a cheap but new 1Mbps switch)
During installation, all computers on the network saw it and had easy access. However, configuration wasn't that simple due to the many options, requiring some reading and searching.
After a little effort, I made all the office PCs have access to the NAS data and work from there, our mobiles have access via the web to the entire file, and a laptop I have when working externally has a part of the overall file on its hard drive and synchronizes it with the NAS via the internet. (I say a part of the file because that's what I wanted, otherwise the whole thing)
I have created two accounts, one for full access and one for read-only. For example, mobiles only have codes for reading.
I used to work with Google Drive as a team with other users, but now I have taken my files from there and transferred them to the NAS. So I shared some folders on Google Drive that synchronize, and the team was not affected.
I have very positive comments about Synology's software. Small programs, well-organized without unnecessary elements.
I set up the NAS in RAID 1, meaning it writes the same things to two hard drives for safety. Nevertheless, I will occasionally keep a backup on another external drive. I also set a reminder in eight years to change the drives. Everything eventually breaks, like the drives of my previous NAS.

I have been using Synology NAS for 9 years now, starting with a DS1511+, then a DS213+, followed by a DS415+, and finally a DS916+. I should note that I have only had one negative experience so far, when the DS415+ broke down, fortunately just before the warranty expired - it was replaced with the DS916+. Recently, I decided to upgrade my old DS213+, which I had as a secondary NAS, in order to make off-site backups of the primary NAS data (now the DS916+). The backup is done over the internet directly between the two NAS devices, without VPN, but with encrypted folder duplication (yes, I know there are other options, like Synology's Hyperbackup, but folder duplication is what I wanted). The reason for the upgrade is none other than Synology Active Backup. It's so good that I decided to use it on the secondary site as well. However, the DS213+ does not support it, so I decided to replace it with the DS220+. I mention this to emphasize how good Active Backup is. Overall, if there's one thing that Synology excels at, it's their software. From video/audio streaming/transcoding, to file sharing, productivity tools, private cloud, backup, various servers, and so on, it has everything. Everything is easy to install, stable, and reliable. As for the DS220+, I consider it to be the smallest Synology NAS worth buying. The DS218 and DS220j have too many limitations, while the DS220+ has an Intel processor and 2GB of RAM, expandable to 6GB (for your information, Synology sells an expensive "certified" 4GB RAM module to add to the 2GB that is soldered to the NAS motherboard, without mentioning that using other SO-DIMMs will void the warranty, although users have tested other SO-DIMMs and they work up to 16GB! - although it probably only recognizes up to 8GB due to the processor's limit. I personally chose and purchased a Kingston 4GB SO-DIMM, which Kingston itself recommends for the DS220+, for just 23 euros). It runs all of Synology's applications, including a hypervisor. One example of a project I see for this small NAS is running a VM with Linux for various local functions like home automation and logging. There is also its "bigger" sibling, the DS720+, which has a more powerful processor, but personally, I don't need it. Don't even consider expanding it with an external chassis. It's expensive, slow, and not universally compatible with all Synology NAS devices. As for the hard drives, I chose 2x WD RED 8TB, which are reliable - since 2012, when I started using various WD RED drives, I have only had one fail - they are quiet and don't heat up, and their speed is good enough, with a good price. If one can afford it, the RED PRO drives with a 5-year warranty are even better. I have used other NAS devices (QNAP, Thecus, WD), but for me, Synology offers good value for money and the best software. The only problem I have with this NAS is that it doesn't have 2.5 GbE (the 2x 1GbE is not as fast for a home with a few users) and its often high price. And since I mentioned network connection, don't even think about connecting it to your network via WiFi, especially if it's below WiFi 6. It will be very slow because WiFi is not designed for file sharing. Connect it directly to your router or switch with an Ethernet cable, which should support Gigabit Ethernet. If you have multiple workstations that use many files, or if you do large backups, connect them as well via cable. You will see a big difference.
[Update] Based on the huge problem with the cryptolocker attack on QNAP, I have the following recommendations if you are going to open your Synology to the Internet: change the GUI port to a random one, enable account protection and 2FA, disable the default admin account and create your own, enable auto block, disable or uninstall all unnecessary apps and services (especially ssh/telnet), force HTTPS, run the security advisor, and finally, if you don't need it, don't do port forwarding from your router but use Synology's Quick Connect.
[Update 2] It seems that Synology has undergone a special check in the latest software for the presence of non-Synology RAM. Now DSM gives a warning that my expansion memory module is not Synology. However, it works fine.

I bought it as a replacement for my NETGEAR ReadyNAS Duo, which I had for a decade, when its incompatibility with DLNA (as it was Ready DLNA) caused serious problems with a network audio player. In this case, the entire body is made of plastic, unlike the metal body of the NETGEAR, which initially made a bad impression but I quickly got over it.
Setting it up is a breeze compared to the NETGEAR, which required a PhD in networks.
The operating system is DSM (Linux based) and the CPU is Intel Celeron J4025 2-core. This one has slots for two disks and is expandable in terms of memory modules (in case someone wants to stream 4K VIDEO). As far as up to 2K, I didn't notice any playback problems. It has a plethora of programs at no cost. In my case, I bought MinimServer to stream audio. No problem with both Flac 44.1 Khz and HD 24bit/192Khz. I haven't tried DSD files yet, keeping in mind that I don't downsample on the server before streaming, but leave the playback to the DAC of the network audio player (MARANTZ ND8006).