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).

I, too, prefer disposables, but for a somewhat different reason. One very commonly used surgical item is a sterile suction/irrigator. It's sealed with 8 AA's at the factory, used for 2-3 minutes during laparoscopic surgery, and disposed of. So pretty much anyone who works in a surgical suite that does laparoscopy has a personally unlimited supply of AA's that would be thrown away anyway.

Years ago when I worked in live audio we had a similar setup. Zero tolerance for a performer's mic pack dying mid show because a low battery indicator wasn't calibrated right or someone incorrectly tracked how many hours a particular set had been used, so it was fresh-from-the-package alkaline AAs installed before every set, and a virtually unlimited supply of half-charged disposables to take home afterwards. Plenty would get reused for internal equipment checks and sound checks, but there were still more than enough to go around.

At the time (well over a decade ago) there was still lots of skepticism around recharagables and the extra process involved in dealing with them... but the tech has gotten lots better since, at that time even low-self-discharge was sort of hard to find. I'm sure much of the industry has moved over by now.