After a while you learn to be specific ' -a' (with space) or '-a,', but this requires that you know what you're looking for. Also n/N is easier to jump between matches than /<Enter>, one less keypress.

Another useful trick is filtering with &, &/-a will narrow it down, but you won't know about the sub-commands if there are many matches. I just tried &/hidden on rg and fd and it takes me straight to `-., --hidden` for rg and `-H, --hidden` for fd. And &/case shows all options related to case-sensitivity with the descriptions. Once you get the intuition for it it's not that bad.

Manuals are not perfect but I don't think I would want an AI. I'm frustrated enough when I don't find a flag the LLM insists is supposed to be there and it gaslights me even though I'm telling the stupid thing I have the manual open.