X-Pro 2

I have done Nikon DSLR (D60, then D700) -> Fuji Mirrorless (X-T1, then X-T2 + X-H1) -> Nikon Mirrorless with a Fuji side camera (Z6 + X-Pro2) and honestly, the Fujifilm system is great an all, but I feel like there are a couple downsides. The first one for me is the lenses. ANd I know how it sounds

Are you planning to use your old lenses on the X‑Pro2? Keep in mind that its sensor is tiny and the crop factor will make the focal length longer. You’re not going to get those 40mm you want. I’d say you don’t have to stay with Fujifilm, you could try a Sony A7C or another small full‑frame mirrorles