JohannesB2B

Which CPU do you have? It should be easiest on the newest Ryzen 5000 series, before that it's a bit trickier.
I know from experience that it's pretty hard to run 4 sticks of RAM on Ryzen. You can't always get advertised speeds, unless you have a set of the same 4 sticks of RAM. If you buy the exact same set of 16GB RAM, they will be from different production batches and not guaranteed to work.

You should be able to take anything then.  Power isn’t a concern.

Use DDU to get rid of the nvidia drivers...
 
https://www.guru3d.com/files-details/display-driver-uninstaller-download.html
 

You should be fine to slot it in but be warned that your windows may be deactivated because of new hardware

3600 + B450 Tomahawk MAX is the ideal choice. But if you can't find the Tomahawk MAX then one of the cheaper x570 boards will do just fine too.

That's a Good PSU. No need to upgrade that at all. 1660 Ti is not much slower than 2060. I would avoid 10 series now unless they are much cheaper. With nvidia after a few years the performance of the 1070 will be the same or worse than the 1660Ti. 10 series is quite old really released 2016.
 
Do not upgrade now. The next generation of CPU for your motherboard (Zen 2) is going to be released before August this year. The new Ryzen 3000 series will be at least 20% faster and upgrading will be cheaper as the 1000 and 200 series ryzen will get a price drop. Also you should be able to overclock to 3.8-4Ghz with your current CPU.

I see that you care about high framerates not the quality and resolution, this means that you are a real gamer ? but you got to consider that higher framerates will be much more CPU intensive, so even if you lowered settings to get higher frame rates, you won't get it! without a capable CPU and you will experience an extremely variable framerates with micro stuttering which will be really bad for gaming experience, I think you definetly need a better CPU with your nect upgrade.
I recommend the GTX 1070 because I recently found decent deals on it.
you also need a better CPU
recently there were big deals on them.
any ryzen with 6 cores 4.2 GHz can boost your frames, but hold on higher frames will also require dual channel 2933 with low timing CL15, don't listen to those guys who say it won't make difference, no! it will as long as you are going for 144 frames

If you want the ray tracing technology - then yes. Otherwise either of the two I suggested will do for 1080p