I had a FD adapter for my EOS R but sold it. I didn't have any existing FD lenses but was interested in them. I bought a few and played around with them but decided that none of them offered any advantage over EF lenses in any aspect for photography. In my opinion, it is better to buy more modern EF lenses. But, that is just my opinion and we all know what that is worth.....less than 2 cents when adjusted for inflation.
Having said the above, I do understand why videographers like them because of the "look" they get in their videos.
To each his own....
