well, there's alot to unpack in the question, i'm going to narrow the scope to jan 2019-now and assume you stopped late 2018 pretty close after the game started, but here are the main changes iirc (someone please correct me if i'm wrong or forget something, i'm old):
permanent features:
- fishing hole (early 2019?): unlocked at resto level 8, buy bait with gold to buy ingredients to make dishes, fill airship, do deliveries etc, very helpful since you no longer need to sweep stages for ingredients and can stockpile stamina for gate of trials
- balcony (early 2019 as well?): feed vip guests for fame, gold, seasoning + get souvenirs to boost fame, gold, item earnings, quite important for resto ranking imo
- do it all king (~mid 2019): unlocked at level 30, get 2* rum for completing a bunch of tasks, very helpful to get a very useful unit!
- cuisine review (i can't recall if it was 2018 or 2019 oops): unlocked at level 31, feed some angry clouds(?) dishes and get embers and M toast
- top showdown (mid 2020): weekly event to fight an npc team of food souls to get rewards like tonkotsu/weisswurst shards, mirrors, gold etc + ranking cross-server
- sky tower (just last week, so you can see how deprived we are of perma features): catacomb-and-tsd-combined-style, fight against teams of npc food souls to get black truffle shards, embers, crystals etc
events:
to be honest, you've missed A L O T of ranking units, including the ones necessary/helpful for the current reso and brave metas (more in a bit)
ranking-wise, we've had turkey, mapo, oyster, white truffle, souffle, longjing tea, natto, croissant, junmai, minestrone, cordyceps, matcha while summon-wise some noteworthy units would be be wuyi dhp, candy cane, martini