Selecting the appropriate text is already a challenge in so many circumstances. Having to tap again exactly inside the selection, then choose from the floating menu are two more failure points and interaction lag.

It's especially painful when trying to select single characters (which happens a lot in CJK land).

I wish I could join the GBoard team for two weeks, just add an optional ctrl key, and quit.

PS: Actually, mapping the physical Volume Up to Copy, Volume Down to Paste whenever there's no media playing or some other condition could be the best choice.