I have an F4RR, which I think is fabulous, but I would probably have the F3. Not entirely sure why, the F3 seems more comfortable, slightly less likely to lose one's license, and the fact that MV are no longer making the F4? That might mean that the F4 becomes more collectable, a highly speculative concept, but the F3 is an ongoing model.
I too have the F3 RC (2018 model / colours) and much as I love the bike, I still sometimes think I should have gone with my original MV love and the F4 RR (but now I now what the RC's are like it would be one of those).
If it was me and the brass was / is taken out of the equation, then I'd go for it. You could always swap back if it doesn't suit for whatever reason, but I live with no regrets and would hate to be a ripe old man, sitting in the nursing home dribbling down my chin, wishing I had taken the plunge and bought / swapped my F3 for one during 2020 after the Covid pandemic..........just saying
Definitely the F4RC, as stated it is a very special bike. No disrespect but the F3RC is really nothing more than a paint job (and a box of goodies) while the F4RC has some special parts. I own a F4RR and a track F3 675 which is kitted with better parts than come stock on the F3RC. On track they are both good fun, I cant say I prefer one or the other but the F4 does feel more special and makes you feel more special when you get it right.