HELP with my upgrade. Would you change anything?

Solution
With Ryzen, the faster, the better, just don't keep pushing the budget if the performance per dollar of the RAM starts worsening too much. Go with the Sapphire, and you can overclock with the B450, but almost sure that the x470 will be better for that, although you won't need to overclock the CPU unless you go for a >100Hz monitor.
If you can get faster RAM, even better, but the build is fine. Anyways, isn't there any other assembler for the Vega 56 with a not much higher price? Some people says that Sapphire is fine, some not... Personally, PERSONALLY I feel like I have seen as many threads about Sapphire cards dying as all the other brands cards together.
 
With Ryzen, the faster, the better, just don't keep pushing the budget if the performance per dollar of the RAM starts worsening too much. Go with the Sapphire, and you can overclock with the B450, but almost sure that the x470 will be better for that, although you won't need to overclock the CPU unless you go for a >100Hz monitor.
 
Solution
Yes there is a point of OCing an R5 by getting a 2600 and using the spare cash to get a decent tower cooler. Keeps it over 4Ghz rather than relying on boost, cooler which helps with boost even if you’re not OCibg it and you might even be able to push it to 4.3/4.4.

Remember the “boost” clock isn’t all Core