You can use any watch who is supported by gadget bridge.
It has an automatic link to an Endurain account.
https://gadgetbridge.org/blog/release-0_92_00/#feature-highlights
Use a Xiaomi watch. It's cheap and let you test your setup without ruining you wallet.
https://www.mi.com/fr/product/xiaomi-smart-band-10-pro/
Or you can use repebble watch. Fully integrated with gadgetbridge because it's open source.