I have a 2600x. I can say even with the JEDEC 2133mhz ram (def settings) i get over 200fps in tf2. You might be doing some things wrong. I know the stock cooler is a piece of garbage though and im sure if you buy an aftermarket air cooler you will get 100-200mhz more.
Several things may be able to do:
You can PBO and undervolt and you can get some nice performance gains. Normally i only have 4ghz too, but i can get 150-200mhz extra by doing it. Watch buildzoids video on how to do it, its nice. 2nd gen ryzen PBO is quite dumb so its pretty much necessary : https://www.youtube.com/watch?v=YQ8zdprzEjI
Second: set a static vcore voltage. I set 1.3125v in the bios with load-line calibration.get like 1.29v. This way i "break" precision boost 2 and have better clocks, therefore higher performance. Ive used this and seen no adverse effect on my cpu. You should run Cinebench or something to find out what the CPU naturally sets the voltage to and sort of work around that. Your CPU wont downvolt at idle if you do this.
Third: Manual OC. Most 2600xs, especially if its 2019 era silicon can hit 4.25ghz with 1.35v. I can hit that with 1.325v. But of course you need good cooling to do that. Ive found manual OC takes more time to tune compared to PBO+undervolt. And around 1.33-1.35v is the maximum you can do with good cooling on these chips. I wouldnt do this because your manual OC clock speed will probably be lower than your normal clock speed ingame.
Fourth: Memory Overclocking. You probably have bad memory chips as it is 3200 cl16. But that doesnt mean you cant keep the same effective timings but increase the memory frequency. You would want to do that to increase infinity fabric link speed. Most 2600xs can do memory speeds of 3333 to 3533. Use Ryzen DRAM Calculator and follow some guides on how to properly overclock your memory. This can be risky/annoying to do so i would save this until you are absolutely desperate. Just remember if you do this memory testing for 24/48 hours is imperative.
as for monitors im not in the know but im sure some people will tell you what is the best. Sorry for the wall of text :>