Buy the 2600 and grab a noctua nh12am4 with the saved money. Just bought those two recently and can't even get my PC to hit 60c. 10 min stress test only hit 56 and gaming typically around 50 or lower.
You don't really need to overclock it, the boost works very nicely. I overclocked for benchmarks to 4.0 very stable with only minor bump on the voltage.
I woulsnt consider keeping a stock 2600x cooler, it's only slightly larger than a 2600. With stock cooling I hit temps as high as 72 under minor benchmarks and now I can't even clear the 50s. Went from idle at 40c to 27-32.
The x bumps up to 4.1 and I would assume a stable consistent overclock would be 4.2 or 4.3 since the non x goes from 3.9 to 4.0 or 4.1. You can safely run at 4.0 when you need that boost while gaming. So you give up basically no fps and get a better cooler.
I don't know how the gaming pro board is, but I have the b450 tomahawk and it's amazing. Technically the gaming is in a higher tier according to msi website, but I like the back panel much more on the tomahawk. Tomahawk lights can be adjusted via msi software, that red light is not only red.
I was torn between the gaming pro and tomahawk. I was able to find more reviews with tomahawk and everyone I know plus on here said tomahawk and I don't regret it, but I think they are basically the same.
I don't know about the 212 cooler and I have not owned a high end heatsink before this one. I did a ton of cooler research and this brand always came out on top. might be the best cpu upgrade I've ever made outside of getting a SSD.
212 does cost half though. Noctua does guarantee it won't get in way of the ram. I have so much clearance by my ram I could use any giant stick and the gpu also has far more than enough clearance. I've seen many that come very close to the gpu. Also you get clips to attach any 120mm fan on the back for 2 fans. This is how i put mine with a xheaper fan on the back. They say it only makes a few c difference