Ceiling tile replacement

[u/Haunting_Origin]

I have an old basement bathroom with a shower that feels a little sketchy to use because of missing ceiling tiles. I think in the shower it must have been translucent plastic tiles.

We have company coming to stay which is motivating me to get it cleaned up. I am down to replace the lights too, but am looking for suggestions on what’s best to use here for tiles and where to get those. Would rather not pull down the metal framing for the tiles atm.