They must have swapped roles at some point, Elementary lets you minimize windows the last time I checked (use toolbar or gesture), and GNOME doesn't 😂
I honestly don't mind lack of visual customization as long as the design language makes sense, is clear, is consistent, and applies to all the system apps and default utilities. In the case of Elementary and GNOME this is OK IMO because they are ridiculously consistent, and share some similarities
I always setup minimize and close, maximize is double-click anyway. If there is only single close button I sometimes just press it for no purposes to realize fuck I closed the window again!
Gnome is amazing, without it I probably wouldn't bother with Linux. Honestly nothing comes close UX-wise for me. I don't want yet another Windows clone.
Minimising is a misuse of the gnome workflow, ideally you'd move a window to another desktop. Better than hiding it in some dock IMO.
Maximising I literally never used the button for anyway. I double clicked the title bar, dragged the program to the top, or pressed Super+Up. Aiming for a relatively small button just feels worse than all of those. It's literally a pointless button and I feel like the only reason anybody has it it just because they're used to seeing it/having a Windows UX.
It's fine that you want your UX to work like Microsoft's, but that doesn't mean others are bad.
E: people get really upset when you point out that their Windows clones are windows clones lol. It's not an insult.