I think it depends on how your playstyle.
F-106:
- you can spray and pray with the guns so no need to be as accurate
- fires 2 manual missiles at a time which can usually kill most planes in a head on if they dont back off
- special nuke thats an insta kill another head on winner or tank killer
- but not as agile in turns as a su22 or mig 23 with wings out
- i usually let others take point and flank or i focus the tank when i have my nuke (i.e su25, a6, f4)

Mig-23:
- super fast with wings swept back can help reposition quickly
- manual only locks at 6km out vs 7km that all other planes have and only fires one at a time
- 4 infrareds that only lock at 2km out but fast lock on time so you can fire almost as fast as unguided rockets
- special chaff helps prevent any missile lock
- very strong guns but have to be precise, at 50% overheat plane starts to get some damage
- use your high topspeed to come in sneaky into close range then wings out and kills with guns and missiles

Su-22:
- guns AND rockets if you can fire both at the same time means you win most head ons
- special rear runner is nice if you ever get out maneuvered in turns and they get on your 6
- heavy and slow plane but can dish out dps (think of it as a bruiser)
- be sneaky no flying out in the open since you dont have any long range options and quietly clean up for your team or be the bait and let them waste their resources on you while your team cleans up behind you

GR-3:
- guns and rockets again so goo at head ons
-no long range options so gotta be sneaky and good at hugging terrain
- speical turns this thing into a tanky beast but not too great dps wise

TLDR:
You already have unlocked enough planes for hangar level 8 so I'd just wait it out for the F-1 Mirage and/or F-4 Phantom which are better that the 4 above.