IMHO, yes, absolutely.
I used my trusty EF 100-400Lmkii with the ef-rf adapter on initially an r7 and laterly, an r5.
It was fine, but I find that the RF100-500 focuses better / more quickly / hangs on to focus better in AI mode, and just feels less 'clunky' than the 100-400 / adapter set-up...