My guess is one of two things they’ll do since thunderbolt 5 was announced a couple of days ago too.
They’ll either put thunderbolt 4 on the pros next year with 40 gig like the iPad Pro has, and regular usb 3.2 gen 2 like the iPad Air does, with the rumored SE getting usbc with an A16 chip and usb 2 like the base iPad.
Or, they’ll go with a four tier model and introduce the long rumored ultra with thunderbolt 5 and 80gig speed, the pro getting thunderbolt 4, the regular getting usb 3 gen 2, and the SE keeping usb 2.
The spring event when they announce the M3 Macs will probably give a clue to it.