User endorsement:

I use this with a lenovo WatchX and it works well. It is pretty basic so you can join the party and hack if you feel it. WatchX is very cheap. ~USD $30 on aliexpress.

I would not ever go near the lenovo watch android app which I consider to be on par with radioactive toxic waste.

Using gadgetbridge & Watch X is superior to the Apple Watch & ecosystem at about 1/10th the cost. Recommended.

I'm finding the S2 instead of the Watch X, is that what you meant? Or if you mean watch X, do you have a link?

I use this with a Mi Band 4! The initial steps to get the Xiaomi DRM Pairing key to actually connect it are a bit of a pain (which isn't the developers' fault), but once you've done that once it's a seamless experience. Huge props to the developers!

I used this with miband, but then xiaomi went full-google and requires their watches to connect to their network before the first use.

I wonder if I can buy a second hand miband and get around that.

You can still get the key from huami servers and say good by to xiaomi scientists checking your data.

Can you do that without installing their app which will have access to your contacts and location upon first access?

Well, you need to install the app at least once, no need to give it full permissions. You might also use a burner device. Once your device is paired, you can remove the app and go to fetch the key.

Search for huami-token on github or for Huafetcher (android version of the same) on Codeberg.

And read our wiki

Disclaimer: I did the Kivy wrapping of huami-token for Android.

If only Wyze Watch were supported...