Thread fitting cap self-sealing or something like that?!

Hello everyone, I have 2 open pipes in the dismantled kitchen that I want to close. For this, I need 2 self-sealing caps with the roughly determined dimensions shown in the picture. Where can I find something like this and what are these measurements? Thank you very much!

In every hardware store. How about simply replacing the angle valve, then you don’t need any caps or do you want to keep using it like that?

Even if you continue using it, I would properly redo this part and not try to cobble something together now.

By the way, these are imperial sizes. You have 3/8" and 3/4".