There is also huawei band, which has similar low price but with seemingly better software than the xiaomi smart band. At the very least, the sync process is easy on both android and ios.

It also works with Gadgetbridge without having to pair it in the official app first (for Xiaomi bands, you need to do it to extract a key, not sure how consistently it's doable nowadays). Apparently the supported featureset is not as complete as for Xiaomi devices, but seems to be enough to cover the basics.

So Huawei are also easier to use without having to send your data anywhere.