There is not GMS on new Huawei devices, and because of the license of google and Huawei sanction, Analytics, Crashlytics, and FCM are not working on these devices. How could have these libs work on Huawei devices?
- add both GMS, HMS, and code branching?
- ignoring these devices!?
- use or implement independence libs of GMS and HMS?
Which one could be a good way to consider maintenance in mind?
Although your question is very opinion based, both GMS / HMS code branching or implementing independence libraries are clearly the best options. At first glance it may seem as more maintenance, but it gives you a window to not be stuck in single market, and with the right abstraction layer you may end up with a nice implementation which requires not so much maintenance and can be expanded to other future markets.
I wouldn't go with the option to ignore devices, as the sanctions will eventually disappear.