I'm pretty sure there are apps that can sync stuff like photos across Android and PC (I think Microsoft has some even). Not sure about iOS since Apple seems to want complete control and forces people to use iTunes (which that's a big annoyance for me with Apple stuff on PC, and since they're ditching iTunes on Mac makes it kinda extra frustrating). Pretty sure you can unlock your PC using a smartphone (and would guess a smartwatch as well). Microsoft added that capability to Windows 10, and I know Samsung was showing off unlocking their own laptop with a Galaxy phone. Which I think there's quite a few PC laptops that have fingerprint sensors or other unlock (Windows Hello) that makes unlock very easy. Not sure, I believe HP's trackpad is considered pretty good now (I want to say I've seen it compared to Apple's?). Which, I hear a lot of complaints about newer Macbook keyboards so its not like Apple is just flawless. Why not 3:2 which should probably work even better? You can get that on some Windows laptops even. I think there's several Android phones that have that (I can unlock my like 4 year old LG V10 using face unlock, and I know newer phones have that; plus I swear its every other year that some Android OEM touts gesture control like its some amazing new feature even though it was done before; LG I think was touting it this year on the G8 and V50 even talking up being able to unlock your phone by having it measure the blood vessels in your hand or something silly). Not sure, but I doubt that's as rare as you make it out to be.
I'd guess you could keep your Apple Watch and use it with a Windows PC and and Android phone and retain a lot of the functionality you want. There'd be some extra hassle for you to setup but once you did it should work. Which, hey its your choice, and I understand some of where you're coming from, but some of your complaints make it seem like you have not actually used many non-Apple devices for quite some time and seem to have bought into Apple acting like they're the only ones that have done a bunch of that stuff (when often Android will do it like a year or more before, but it doesn't become popular, then Apple does it and it does, which then leads to the Android stuff to add it back). Which, I'm not saying you won't have any issues, but then I see lots of people all Apple that have plenty of the same issues (syncing things how they want, things like Bluetooth "just working").
Which I'm fairly certain you do in fact have to configure a lot of that stuff on Apple devices. And maybe your point is you've already gone to the trouble of doing that so its an extra hurdle to you switching, which is a fair criticism (but its also why I hate these stupid walled garden "ecosystems" that all the tech brands tried to force on us to lock us into their stuff; I think they should be made straight up illegal as they're blatantly anti-competitive; they have worked to try and make transitioning between iOS and Android easier, but I'm sure its still a nuisance).
I agree with some of your points and I've been quite critical of Android as well, frankly both iOS and Android have lots of things that bug me about them that I have no clue how people put up with all this time. Apple has loosened their hold some (although I think a good amount of that is being relegated to iPad OS, like widgets and file system browsing). I like a good amount of aspects about Apple's stuff, but there's enough that bugs me still (one being price, which sadly Android OEMs seem like they're just following suit, and that's ridiculous; which Microsoft started doing the same with the Surface line and that bugs me too - I don't mind a premium but stuff like the Surface Studio are ridiculously overpriced while also being saddled with stupid limitations).