Go for it!!!
I am 63yo and was an avid sup surfer for years, I now pretty much only sup foil and love it.
I feel regular sup foil surfing is not that hard on the body at all and I enjoy the fact I can get enjoyment in much smaller conditions (so can avoid getting flogged by the big sets

) and can avoid the crowds more.
I also downwind on sup foil and do some flatwater paddle ups etc, this starts to get a bit tougher on shoulders and legs etc as you have to put in a lot more effort to get on foil.
I actually enjoy the workout though and will be avoiding a foil drive unless I really have to as I get older, as I believe in use it or lose it.
I do find that where I used to be able to catch waves that no one else could I am now regularly competing with foil drives so it may get harder and harder to get waves but I do find most of the foil drive crew respect the fact that I am still just paddling and allow me to get a few.
So in summary sup foil surfing is not really much different than sup surfing unless you start pumping a lot to get back out or link waves.
That is not necessary though and you can just paddle as you would on a sup and when paddling back out I stand in a more parallel stance and paddle on both sides anyway pretty much the same as sup surfing.