I think the GOTM22 download for Mac is only available as an extension pack. If so then you do need to go back to
GOTM20 v1.29 , I think and download and install the full pack from that game, then install the Mac add-on packs for GOTM21 and GOTM22.
To check you are completely up to date you should finish up with the following add-ons in your art/leaderhead and art/units folders:
Extra races (based on my /art/leaderheads folder contents:
- Keltoi (BR.pcx, BR_sm.pcx)
Vikings (files with Dal-Riada names)
neoCarthage (HA2.pcx, HA2_sm.pcx)
Ottomans (OttomanCrest files)
Spain (SPA ... files)
Minoans (Strathclyde ... files)
Extra units (based on my /art/units folder contents:
- arabian caravel
azap infantry
balkan dragoon
defense
eqWorker
european swordsman
f0g (with a zero)
fanatic
fog (not sure of the difference!)
frankish axeman
galleass
galloglass
medieval swordsman
militia
muslim caravel
peltast
persian mercenary
pictish warrior
separatist
settler1
settler2
spanish missionary
spartan hoplite
squid
treasure
volcano
wallcross
worker1
worker2
These are not all the files you need ( and I might have missed one or two

), just indicators of whether you have installed all the packs. There are essential text files as well, and a "resources storage" folder. You might be able to play any individual game with some items missing, but you'll probably then fail on your next GOTM, so it's best to get all the packs installed.
[Edit} Cross-posted with Trixter. It looks like he has the missing piece of the jigsaw - Cracker's post giving the GOTM21 Mac add-on link, so use both posts for the complete picture.