Assuming this is a 2012 Mac Pro? If you need to use a 10+ year old computer, then you need to use it and upgrading "all the things" is just what you have to do. Personally, I would never drop $2K to upgrade a 10+ year old computer.
I predict this thread is going to explode and you will have to sift through the weeds to find a helpful reply. Since I'm first, I'll be the first weed
Here's my controversial opinion: Don't upgrade it, just get a new computer.
I tried to run a 2010 Mac Pro for awhile, and the CPU architecture itself is just really old, you can only take it so far. For $2000, you might as well get a Mac Studio, or a PC workstation that would blow the Mac Pro out of the water.