It can't do the literal entire thing an operating system is supposed to do: manage applications and their resulting windows, in a sensible way.
I want to know what application is running.
Sure it's in the dock!
I want to find a specific application window.
Go fuck yourself right to hell.
Wait, the taskbar doesn't show the running windows, like it does on every other OS? It's at least discrete right?
It discretely takes up 1.5cm of the bottom of the screen at all times. It's so discrete it doesn't even need to use the corners.
Uh, alright, well that's all the system space you need right?
Yeah of course just that bottom inch or so .... And a top of screen system level menu bar to display what windows does in the bottom corners.
/sigh/ ok, fine, I just want to be able to full screen a window and still see what else is open.
Burn in hell and die.
I want to be able to easily switch left and right between open windows.
Go full screen or I will shoot you.
I want to move an open window into the other monitor.
You can't because you're full screen dumbass.
I want to let a window present a popup like they normally do.
You can't because youre full screen dumbass. Why would you be full screen?
I want an application like Slack to be able to popup and remove notifications when is appropriate.
Choose to have every single notification persists on screen until you manually remove it, or miss all your notifications.
Can't we trouble you for something in between, where we trust an application and let it manage them in a way that makes sense based on their context?
You can trouble me for something in between these cheeks, shit stain.
Like honestly, I fucking hate what an advertising and AI filled mess Windows is, but it can actually manage your windows and virtual desktops in a way that makes a modicum of sense.
It feels like a single Apple product manager decided that the way that they use their computer (a single application at a time, no windows to manage) is the only way anyone does, so who cares if we implement a nonsensical full screen paradigm, it makes one tiny niche edge case slightly simpler.

I mean it doesn't pay the bills, but it does get you respect from other speed runners and from people who respect speed running.
It's also somewhat a matter of your specific hobby ... speed running video games is pretty niche and useless compared to most hobbies.
Like on one end of the spectrum, there are hobbies that help everyone, like volunteering, cleaning up or beautifying your community, helping friends and family and loved ones, or organizing community programs.
Everyone is going to respect the hell out of you for that, and it's pretty easy to see those translate to jobs if you needed them to.
Then there are hobbies that can be beneficial to you or to anyone, like hobbies where you create stuff (whether it's knitting, 3d printing, home renos, gardening, cooking, etc). These are much easier to use to help others, and to turn into side hustles if you want to.
Then there are hobbies that you like that create community and socialization, from playing team sports, to DnD groups, to parties, to multiplayer video games, to organizing dinners and events.
Then there are hobbies that primarily benefit you and benefit the community only indirectly (in the sense of you being a better or more capable person). This includes stuff like running, weight lifting, reading a book, etc.
Then there are hobbies that don't even really benefit you but you do anyways, like watching TV, scrolling social media, or getting slightly better at a pointless mechanical skill.