Must admit, I made the decision a few years ago to go Canon FF rather than pursue the Fuji system. I made a good choice I think but I do still love my little T-10, I still have it and with the kit 16-50 and the 50-230, it's a very compact, walkabout set up that I can use for local walks and saves me lugging the Canon about.
One thing I wish though, is that a 3rd party telephoto lens was available. I know the 100-400 is a dream lens but I can't justify buying that for what is a second system for me. I bought the Viltrox adapter, that allows me to use Canon glass on my T-10 with AF. AF is reasonable, I know it's not going to be as good as native glass but it's workable. One thing I hadn't realised, so it's my bad, is that the centre 9 AF points are PDAF, so next time I use adapted glass, I will be using just those 9 points.
I have considered a new Fuji body with better AF but that's getting into Fuji tele lens money.....but
What about a used X-H1, could I expect better AF performance than on my T-10 with adapted glass? I know it won't be as good as native but for my intended use, an improvement would do.