FEH Pass is only worth it if you’re after something specific. Is it worth it for 5 orbs? No. Is it worth it for 50 extra grails? Maybe if you need grails because too many projects. Is it worth the Divine Codes? No. And the units are going to depend on the fodder or how much you like the unit. In general, I think it’s pretty worth the price, but it really depends on how much you need or want what it’s offering.
As for the meta, speed is king, dragons and armors are dead, and they seem to be focusing a lot on Flying units lately, so that may be the next step in the meta. Also Resonant Battles exists, you missed when it was terrible and now it’s kinda fun, but there are new Harmonic Heroes that are only really great for that game mode and are otherwise just “Duos but kinda worse.” Arena’s score creep keeps going up, and now you can hit 190BST with Duos. Aether Raids is kind of a cluster and the rule changes would take forever to explain but the short is offense is way easier now.