Building the mouse Logitech won't make

My favorite mouse is the Logitech Anywhere MX. It's highly comfortable despite being pretty small. The back/forward buttons on the side are indispensable for web browsing, file management, and switching weapons in first-person shooters. It takes two AA batteries which last for months and take seconds to swap out. The dongle is small and has good range. The scroll wheel switches between clicky and free-scrolling.

It's pretty much the perfect mouse, IMO, to the point that I built up a back stock by hoarding new and open box on eBay. But there are two main problems:

1) The the microswitches go bad after a couple years. It's possible to replace them, but it's tedious and you run a very real risk of damaging the PCB (as I have already done).

2) The dongle is USB Type-A only. Logitech actively refused to make a USB-C unifying receiver. I assume they wanted to shift to bluetooth but they still made unifying receiver devices for years and years after bluetooth was everywhere, so I dunno.

As far as newer iterations, the Anywhere MX 2S is somewhat tolerable, but it has a built-in battery which must be charged every couple of months, which is annoying. All of the newer Anywhere MX mice are even worse because they changed the basic functionality/features of the mouse with each revision. Oh, yes and they cost $90 (!) retail now.

So basically one of my side-projects, one of these days, is going to be to try building an open source Anywhere MX clone. Should be a fun yet challenging endeavour. I know there are a bunch of online communities making their own keyboards from scratch and at great expense, is there such a thing for mice?

Not sure about online mouse communities, but it intrigued me that you prefer replaceable AA batteries to built-in rechargeables. I realise now that because of my dislike (leaning towards hatred) of single-use alkaline batteries I unwittingly dismissed the benefits of having quick replaceability.

Nickel metal rechargeables are a good AA/AAA substitute for devices designed to tolerate their lower voltage. For more power, 14500/18650/21700 cylindrical lithium cells are my go-to.

Personally though, I find it more convenient to have a charging cable on hand vs keep some charged batteries on standby. When the built-in battery eventually goes bad, I am confident that I could replace it myself (not a universal position).

Had to use my old TI 89 one day. Haven't used it in 10 years. Took it out of storage, put in 4 AAA usb-c rechargable batteries, worked like a charm. Could you do the same with your hard to replace custom battery?

Any consumer electronic using standard format batteries is superior by default. Because 10 or 20 years from now, it still have brand new full batteries lying around.

I have an early digital video camera with a genius design. It came with a custom rechargeable cell in the battery compartment. But the compartment _also_ supports regular AA batteries.