Exactly what the other reviewers mentioned...
The app is not available on the Play Store and that's because according to the company I emailed, the product has been discontinued, so I found and downloaded the apk (Thermopro Home) through Google and installed it on my phone.
I also provide the disappointing response I received from the company regarding this issue,
"Jeremy Kushner (ThermoPro)
Jan 9, 2024, 3:03 PM EST
Hello,
This model has been discontinued and the APP no longer works.
Sincerely,
Customer Service Representative"
The astore from which I purchased it never responded to my email regarding the app.
As for the rest:
It connected with moderate difficulty, meaning I had to try 3-4 times and the router - device - phone had to be next to each other. So I had to connect the device to a power bank, bring it next to the router, establish the connection, and then place it where I wanted it.
The app is not particularly stable, after 4-5 times it opened-closed, it even crashed (Samsung smartphone with Android 14). Clearing the cache didn't work, so I deleted all the app's data (including history, account, etc.) to make it work again.
The app only has a display for 24 hours and 7 days.
The fan does make quite a bit of noise, I don't know if you can tell from the video I uploaded, but it doesn't seem to be intended for use in a bedroom, for example, but for other spaces where you won't be sitting while there is quiet for you to rest.
The provided cable is short (around 1 meter).
At least the sensors from the two products of the same company are compatible.
For anyone wondering, one product connects via Bluetooth and uses the Thermopro Sensor app (which is also available on the Play Store and is stable), while the other only connects via 2.4 WiFi with the Thermopro Home.
I bought it for 46 euros and I don't think it's worth it except if someone really wants the WiFi feature because I couldn't find it in any other product. However, even this comparative feature has problems.

For me, absolute accuracy doesn't matter much, because there is a difference from reality but it is consistently off by 0.7 degrees. I know the exact temperature. My issue was with the application (ThermoPro Home) that the Manual suggests, it doesn't exist in the play store. Instead, (ThermoPro sensor) appeared, which I downloaded and the pairing process became a nightmare. It just wouldn't work. In the end, without calling the main office, I searched on Google for (ThermoPro Home apk) and found it. I downloaded the apk and ignored the warning about unknown sources and installed it. Everything worked smoothly without any disruptions or disconnections.

Good product if you manage to connect with it. Once you take it out, you have to follow some steps to integrate it into your Wi-Fi network, which only supports 2.4Ghz (If you only have 5Ghz, you're out of luck, it won't work for you). And in general, it's a painful process, took me 4 days of struggling, but I read some reviews on Amazon and cleared the cache through the app to make it 0kb, and in combination with trying it with another phone, I managed to find it and connect it to the network.

It is perhaps the only thermometer-hygrometer with Wi-Fi that plugs into the socket (without batteries), and that's why it was purchased. €46 16/11/2022

POSITIVES:
- It's Smart/has Wi-Fi, which makes it stand out from the others because you can check the humidity and temperature of the room wherever you are, as long as you have internet on your phone (only through the app, not via browser).
- Small
- Comes with a plug, not batteries
- The app shows a history
- Other people can connect to the app to view it.
- Very good company and very good support

NEGATIVES:
- The initial pairing gave me a hard time (I have a poco and it didn't work, but eventually it worked with oneplus, then I connected with poco and everything was fine)
- The fan at the back makes quite a noise if it's quiet.