FWIW, my thinking is:
Get RF 24-105 f/4L IS unless you would really value the (semi) macro mode of the EF 24-70 f/4L IS, in which case get the EF 24-70 f/4L IS. (Once you add the EF/RF adapter, the EF 24-70 f/4L IS wouldn't really save you much, if any, size or weight, so I have ignored size and weight differences.) Since you own an R camera, I wouldn't even think about the EF 24-105 f/4L IS II.
To try to explain my thinking ... I have the EF 24-70 f/4L IS and I have used the EF 24-105 f/4L (original version). I prefer the IQ of the EF 24-70 f/4L IS, and the macro mode and slgihtly smaller size and lighter weight are nice bonuses. Everything I have read is that the EF 24-105 f/4L IS II is very similar optically to the original version. The mark II is notably bigger and heavier too. I haven't personally used the RF 24-105 f/4L IS, but from what I've read and seen it is at least a bit better than both versions of the EF 24-105L, it's about the same weight as the EF 24-70 f/4L IS with EF/RF adapter, and it gives you the extra zoom range. I really do like my EF 24-70 f/4L IS and it has served me well, but if I was starting now in the R system, and I was happy with an f/4 lens (you could always think about a f/2.8
) , I think personally I would go for the RF 24-105 f/4L IS so I didn't need to use an adaper and becasue I would find the extra zoom range over EF 24-70 f/4L IS useful. Anyway, as I've said, I haven't actually used the EF 24-105 f/4L IS II or the RF 24-105 f/4L IS, so probably best to take my views on this with a grain of salt