Hey, I am new to Linux and I tried a lot to fix my problems with Linux Manjaro in the terminal.
PC specs: 5500G, RX6600, B500M Pro-VHD Wifi, 16GB 3600MHz and 2TB Seagate Barracuda HDD.
Manjaro Plasma needs 1,5 minutes to boot and then its still slow and sometimes it doesn’t even react on clicks/input from mouse/keyboard and freezes applications.
And if the system was in the standbye it goes on but mouse and keyboard don’t react again.
before Plasma I used Xfce and Pop OS for a few hours but there were similar problems.
it sounds to me like a problem with the hdd, you should verify the hard disk integrity i use hard disk sentinel. and as Maltavius say you should try an ssd for the OS and hdd for files.
you probabli can test this runing linux form pendrive to see if this problems do dont persist.