Pc problems

Hello to everyone.I have very serious problem with my pc.I bye a pc 11 months ago and every passing weak gets worse and worse.When i play a game stutters,having very bad frame time and some time FPS drop(for example 80 fps to 40 fps).The problem i believe coming from this-GPU usage drops when i play a game,also core clock,power consumption and the voltage.All temps are normal.I did everything i can but failed to fixed.I tried power plan settings,window reinstall,driver reinstall,antivirus program,sendet to service and many usual things that has been dunn in such situation and nothing.Even getting worse in time.Please help.
My specs:
Intel i5 10400f
ASUS TUF RX5600XT
Gigabyte B460 motherboard
16 Gigs 3200mhz cl16 RAM
512 SSD for windows
1 TB for games
600 watt 80+bronze Koling PSU