I may just have to accept the fact that it's not a good idea to try and match sensitivity to different FOV's anyways. I understand that the sensitivity doesn't come out the same and it can translate poorly to other games. The goal was to have 1 sensitivity that I could use across several games with different FOV's but the more I think about it the more it sounds like a nightmare.
For example Hunt Showdown may actually be a correct calculation, but it feels way faster than Fornite by almost 2 full turns and this could just be due to the increased FOV.