Repairing Two Faulty Magic Mouse version 2s

Well, first off I would try swapping the batteries. If it's the battery that's the problem, it would be obvious if you just swapped them to see. I'll link the guide to battery replacement for if you decide to do this. Then I would check the charging port to make sure that's not busted. Otherwise, it would probably cost less just to replace it with a different one, as getting a new motherboard tends to cost more than the actual product. For the second one, it sounds like you got glue in the internal button, thus gumming it up and making it click inconsistently. Your best option for that is probably to replace the button, which would require soldering in all likelihood.

妙控鼠标2电池更换

UPDATE: Based on the picture in the guide, it looks like the charging port might be integrated into the power cable, which itself is integrated into the battery. So maybe you just need to replace the battery after all!