Depends what ram you will be running too.

What about cpu frequency clocks? Are you reaching expected clocks?

Donwload intel xtu and go to advanced tab. While running cinebench there is a graph there that shows various info. It also says reason of potential throttle (current throttling, tdp throttling, thermal throttle, etc.)

Also, are you sure you are not running anything in the background that is eating cpu resources?

3200cl16 is on the slow side. Whether it is bottlenecking or not, its easy to figure out. Just look at gpu utilisation (faster ram is only going to improve gpu util, not magically generate performance out of nowhere). Tbh you will mostly see improvements in minimum fps/1% lows. Also depends whether you wanna invest time tuning the ram or not. Easiest boost you can get (even on your current kit) is trying to run higher trefi value. Just make sure you stress test it thoroughly because you dont want your OS getting corrupted. For ddr4 i would look at either a dual rank 3600cl16 kit or a 4000cl16 kit depending on budget. Just make sure ram is running in gear 1 mode because at gear 2 you are likely to perform worse or on par with 3200cl16.

Probably ram and maybe b760 chipset. Still, i wouldnt go crazy over just about 1000 score. Also keep in mind, if you run cinebench on higher priority then you get a bit more score.

Cpu prices are good, ram prices are decent and storage prices also good. Generally a good time to make a purchase. There is always going to be something new coming that you could wait for. But it will be expensive at release so you need to wait 4-8 months for it to drop to more reasonable levels. By the time you reach that time period, you realise the new gen is coming soon so maybe wait for that… And the cycle goes on. Forget about the longevity of Sandy Bridge. That was an anomaly due to poor cpu performance progress during ~2012-2019 and certainly not the rule. Nowadays cpus can get outdated after 3-4 years depending on what you are doing.

Up to 6400cl32 xmp imo should work flawlessly in 99,9% of cases. 6600-7200 xmp will work most the time fine assuming you are not limited by motherboard. 7600 and higher, it is very likely xmp wont work and will need to tune voltages manually.

Thermalright air cooler options like peerless assasin, frost spirit, frost commander. Other options like ak620 are also solid. No reason to go noctua imo, too expensive. If you want to go overboard with oc then look for an AIO 360mm or higher.

Depends on needs and cpu. I kept my previous cpu (i7 2600k) for about 10 years but thats an anomaly due to anemic cpu performance progress during that time period and me also not doing anything seriously cpu intensive. 2600k had also very good oc gains and hyperthreading aldo carried compared to just 4c/4t cpus. Previously i owned pentium iii -> pentium 4 -> core duo E6750.