I mean, they did it with phones too. Android is just Linux. That was one of the main attractions, for me at least.
At first, many people and groups supplied their own phone OSes. There was a whole thriving community ecosystem. Then they started to make it really hard, locking bootloaders and including critical pieces of hardware that didn’t or couldn’t have open source drivers (look up WinModems for a very early example of this technique, it remains really effective) or otherwise required extremely convoluted methods to access and the phone might function marginally without some of these fully functional, but at least you could still install a custom ROM on it if you were stubborn enough.
But even that wouldn’t last. Nowadays they’ve made it literally impossible to defeat the security on most phones, in the name of keeping hackers and criminals out, but really a big part of their motivation is blocking these pirate OSes that let you actually control the hardware and software in your phone, doing criminally nefarious things like stopping them from downloading ads (the horror!) and preventing them from funneling all your data and activities back to Big Brother (how rude!) and worst of all updating it with modern functionality after they’ve declared it “obsolete”. The goal going forward is to sell you things that you don’t and can’t control, so they can shut them down or make them gradually more and more useless and make you buy new ones forever. They want you to have a subscription for everything including physical objects without realizing that you’ve been forced to subscribe to their regularly-scheduled-disposable-device-replacement-plan for no actual reason.
They’re coming for computers too, or at least they’ll try. They want control of everything we interact with. For profit, mostly, but I wouldn’t rule out other motives. It’s a powerful thing when you have control of everything people see and do.
Chargers for RC model vehicles (car, airplane, helicopter) can do most if not all of that stuff, but you will have to be comfortable with soldering connectors as there is no universal standard connector system for any of the battery types you mentioned, and even standard size 18650/21700 cells are rarely used for RC purposes. The RC hobby has mainly settled on XT60 and its smaller cousin XT30 as the closest you’ll find to a standard, but even within the hobby many batteries use other connectors. Snipping leads and soldering connectors is not an optional skill, the currents involved can be very large and will easily melt a poor connection made with poor skills or some hacky clip-on connector.
For charging, this is the sort of thing I use, no promises. RC chargers also include a balancing system to allow it to balance different cells across an entire battery pack but you will have to have individual wires junctioned in between each of those cells so it can sense their voltage and top them up as needed.
Also most RC chargers don’t bother having anything to do with lead acid (automotive style 12V or otherwise), as they are much too high amperage and heavy for any sort of RC use and they use a wildly different charging design and have much more complex health monitoring and maintenance needs. Not recommended for that, use an automotive, marine or off-grid style battery maintainer and repairer for those. The one I linked says it does handle SLA (sealed lead acid) but I wouldn’t trust it to do a good job. Compromises have likely been made. You’d be better off with a dedicated unit for those if you are going to be dealing with them.