Well they’ve already announced the FH4 servers being shut down (didn’t they ?.. early fall iirc ?) so that probably answers the question of which goes officially EOL first. The reason they gave as I recall was low player counts on the FH4 servers (which, given the state of the game a year or more ago when I had enough is hardly surprising). Granted it still had, probably has, it’s hard core devotees and that’s cool.
The problem with the passionate feelings about Forza in general, and Horizon 5 specifically, is they seem more in the how far it has fallen how much we had hoped for than how awesome it is. Not sure that’s a marketing win 
“no such thing as bad press” mantra aside.
Where was I going with this ? 
I seem to have derailed my own train of thought 
Ah well, I’ll just go yell at some kids on the lawn and mutter until I remember 