Nether portal custom colors like in the Java Edition 20w14∞ Snapshot

Make nether portals with custom colors like in the Java Edition 20w14∞ Snapshot. Can be made with commands and be link-able to custom dimensions as well.

Ps. To be perfectly honest I thought this was a feature that shipped with the custom dimensions update, and I nearly drove myself crazy trying to figure out how to do it for my server but I found out it wasn't possible and hence why I made this post. :(