I pronounce it zaw-sha.
I voted for ZO-sha though like others have stated I pronounce it a little closer to a soft J sound (zh) than to a sh sound.
I used to say zo-see-uh but most people say it as zo-sha so I switched to that
The way it’s said in Polish is more like ZOSH-a, or ZUSH-a, but I know a lot of people anglicise it to ZO-sha. I would advise using one of these pronounciations given that it’s culturally a very Polish name, but of course people are free to pronounce it however they want.
I’ve been saying [name_f]Zosia[/name_f] like ZOSH-ah like [name_u]Sasha[/name_u] with a “Z”, but apparently the proper pronunciation is ZO-shah. This has been a whole thing for me–I LOVED [name_f]Zosia[/name_f] when I thought it was zo-see-ah, but did some research where I thought I heard it was ZOSH-ah, and really went off it then, but apparently neither were right hahahaha. ZO-shah is okay–I still like zo-see-ah more–but I guess now I’ll say ZO-shah, lol!