What should I improve on my PC first?

In the picture you can see what kind of components I have installed. I'm more of a gamer and want to make my PC fast. The graphics card was changed 8 months ago due to an error, now I have the one in brackets. Is it even worth upgrading now? Or is it currently too expensive? I have owned the computer since 09.2017.

Small thing, if I hit my table a little harder, it sometimes happens that my power supply unit becomes extremely loud, as if some cable on the fan is rattling. After 2 minutes the fan will then return to normal. However, I cleaned the outside of the power supply and I also didn't see a cable directly on the fan of the power supply.

My graphics card also gets loud so the fans while playing, e.g. With ETS 2 or CsGo, sometimes also with Fortnite. In the task manager it says that the GPU is almost 100% busy, but the game only says 50% or so… I have already turned down the graphics card settings in part

Thank you in advance

MfG MediumRumpsteak aka Kai

So it would be enough for me in terms of performance.

Should be enough until prices have normalized again.

The graphics card should be used to 100%. Then you have the most FPS.