If you're planning a DIY multi-zone mini split in 2026, Zone Air and MRCOOL...
https://high-wiki.win/index.php/Can_I_Control_Each_Zone_from_My_Phone_with_Zone_Air_or_MRCOOL%3F
If you're planning a DIY multi-zone mini split in 2026, Zone Air and MRCOOL both offer solid options with thoughtful features