iPad, iPad mini, iPad Air, iPad Pro. I dont believe that that is particularly confusing.
If I were naming the lines, I’d adjust them like this:
iPad -> iPad SE
iPad mini merged with iPad Air, simply have 8.3 and 10.9 sizes
iPad Pro - same as before
iPhone SE stays as is
iPhone -> iPhone Air (Plus branding eliminated, simply have just 6.1 and 6.7 sizes)
iPhone Pro (eliminate Pro Max branding, simply just call it 6.3 and 6.9)
Watch SE stays as is
Watch aluminum -> Watch Air
Watch steel -> Watch Pro
Watch Ultra stays as is
MacBooks stay as Air and Pro
This leaves Ultra branding for an even more hardcore iPad and iPhone.
When Vision comes out, Vision Pro. Lower cost lightweight version, Vision Air. Even more souped up version, Vision Ultra. Then a ultra basic Vision, Vision SE.
Easy suffixes to denote the tiers: SE -> Air -> Pro -> Ultra
This way, all Apple mobile devices will use the same aligned branding.
Desktops will be another story for another day.