Get a fairphone and remove the battery.
As long as the phone is connected to the PC and is getting electricity, it will work without a battery like PCs.
Samsung phones have a battery protection mode that will stop charging at 85% when enabled. Any lithium pouch cells will swell up if they are kept on a charger at 100% continuously.
You can use wireless ADB, or try to set the battery limit to 80% and only set charging to only start below 30%.
Wireless ADB settings can be found in the developer options. battery options don't always include the option to require battery level to drop below X% before charging starts again, and if it is, it is usually branded as battery saver feature or smth like that.
Not an android user or anything, but I would assume there are apps to disable charging the battery. Or apps to allow you to use a phone without the battery.
If you can disable charging then I’d discharge to 20% or so then disable charging and connect it. 20% should be a fairly safe storage capacity for the battery. Maybe 30-40 to be on a bit safer side.
Then you could just go through a battery cycle once a month or so to ensure different cells get used. I’m sure you could figure out an automation for that mr tester man.