Ok, I like that victory token idea. Though let me add a twist.
Decks of cards for each faction (or maybe even power) with objectives on them. Some worth 1 point, others worth 2 points, capital captures worth 3 points. First to get to, lets say 7, wins.
The kicker. The decks have about 16 objective cards in them, and players get dealt maybe like 8. 4 they play with face up, 4 face down. So their full motivations aren’t always known.
Perhaps a UK card would say “Have more capital ships than all other powers combined” 2 points
A German card might say “control Iraq and Syria” 1 point
A Japanese card might say “ANZAC has no surface warships” 1 point
The decks could get pretty big, pretty complicated, or as simple as the objectives you outlined.
The bonus is some being secret, others being known.