>>4074296An X-T4 would be better in most situations than a 50sII + GF50, and the 50s/r/sII are pretty rough value propositions compared to just get a high res FF mirrorless from another brand.
The 50sII would get you better resolution and dynamic range, but be significntly slower in operation. If what you're itching for is mostly increased resolution, I would just wait for the X-H2 next month (or X-T5 later). Unless you get more lenses for the 50sII, the X-T4 would also likely be better for lolbokeh and lowlight shooting (because of faster lenses).
I have a 50r, and do use it often, but I definitely use my X series bodies more due to the size and speed. Differences honestly aren't that noticible for a lot of outputs (IG posts, resized on websites, etc), but if you like detail, there is definitely increase.