I believe you are confusing two things here.
1.) The known bug that teams containing an Immortal keep disappearing when leaving and returning to a PvP region, due to the team filter stumbling over the special rule that Immortals bypass restrictions in their home region.
2.) The requested feature of saving and selecting teams for PvP.
This isn’t about the requested feature, this is about the bug that makes using any Immortal highly annoying. It’s already been reported in July, like here, and handled very poorly.
Surly it doesn’t take at least another quarter of a year to finally get this addressed?