I am not sure which you mean..
do you mean pick any culture period, or any culture per era?
if you deselect the 'new' option (its not new anymore really) 'exclusive cultures' you can all pick egypt on the first era (instead of first faction to get a star and move up locking everyone else out), but not like france which is a later era.

there are also mods to start in later eras, and as above you can pick any culture from that era (and possibly earlier ones?).

it does not make sense to start with any culture from any era due to the unique units and some perks not fitting the era you are in. I don't know if THAT has been modded in (whether it makes sense or not) if it is what you are looking for.

I think you are referring a mod to pick any culture (from any era) in Ancient Era right? I think i have not seen any mod doing that, but should be doable. My recommendation is to go to the official discord and asking if any modder could give you a help to create that mod. I can imagine a balance should be requested to have "similar stats"