Magic Keyboard is working strange

Hello! I am new here, I also have a BIG question. Sorry for my lame english. I am having a weird problem with my wired Apple Keyboard. My iMac is late 2015, but it’s still in good shape. I have this keyboard "from the box" with iMac since 2018. It’s been working great until today. The problem is "mistyping" I guess. When I press "4" or "5", it types "45" simultaneously, no matter in what order I press the key (when I press "5", it still types "45"). Same goes for "r" and "t" (types rt), "f" and "g" (types fg), "v" and "b" (types vb). I think there is some logic but then "2" above the letters not working, while numbers on numpad work without problems. Except for "0" on numpad. For some reason, it presses "left arrow" key, only then "0" (and vice versa), it kinda works like "3" or "4" on my malfunctioning keyboard. But weirdness doesn’t end here. If I try to press "z" it acts very strange. But thanks to keyboard tester in browser I saw that "z" is reading "command z", which is undo. With online tester I pressed every key and found new problems. The "2" above letters and "F2" are not reading at all. When "fn" is pressed, it reads as "Backspace". If "\" is pressed, it somehow reads as left mouse button, yet in reality "\" or "|" isn’t typed and there is no LMB click, pointer just disappears. I don’t remember this kind of problem since last week. Right now I am not sure that it’s software problem. You see, I have Windows via Bootcamp, and it has the same issue. Mostly I use it for playing video games with controller, so I don't use keyboard much. I work only on macOS, just got used to it and most of my stuff is here. Last week was holiday, so all I did was playing games. Tonight I discovered this problem. I couldn’t even logged in, it said that password is incorrect. Thank god I had keyboard viewer in login screen. I thought I forgot my password, but noticed that inputed length of symbols exceeded my password’s length. Right now I am typing with keyboard viewer. I tried to restore to defaults in settings, but it didn’t help. I uninstalled and tried to update keyboard driver in Windows. No Sticky/Slow keys enabled in Accessibility. macOS version up to date (12.6.7). Idk what to do. I have no AASP in my country and I don’t trust other "official" apple repairers around here. I know I can just buy a new keyboard and use it, but I want this "from the box" keyboard. It’s also problematic to find original apple keyboard and I don't wanna use other ones. Can you help me please?

Thank you if you have read to this point. I appreciate it.

4545454545rtrtrtrtfgfgfgbvbvb000000000v (just typed via keyboard as an example)

A picture of my keyboard readings from tester: