You won't be able to purchase specific seasons but upgrading to the Deluxe Edition will give all 4 seasons, the 2 dungeon keys, and the exotic auto rifle. Note that once this season ends, all of these past 4 seasons will be removed from the game, but the plus side is that they have delayed the new DLC until June which should give you lots of time to do that.

Welcome to the milking where bungie squeeze every penny out of every possible angle. You need to buy lightfall deluxe which includes this year's 4 seasons, even if you already own lightfall you can't simply upgrade like other games, you need to again buy lightfall. A few tips or warnings depending how you look at it. This year player population is super low, a bunch of reasons for that but this has resulted in older content being pretty much dead. I start new accs every few months when I get bored so play thru it all a lot but this year has been very difficult bcoz there's simply no one to matchmake with, salvage is a 6 man event but you'll be lucky to find 2 other players nevermind 4-5, deep dive is similar, savathuns spire & altars are a little better as are battlegrounds but still long wait times & usually brand new players so it takes a while to get done. If there's 2 of you you can get it all done but may have to try different times to get salvage done, you need it twice for the full quest & it's luck if you find anyone or not. On a more positive note if you enjoy the game it's worth picking up, the content is decent it's just a player population problem that hinders you. Best tip, play through light fall & level up, once you get to 1770+ you'll know if it's worth buying the extra content & you'll match people around your level, so at least players who know what's what. If you go in too low it's painful, a lot of it is 1810 & you'll get shredded, along with whoever you matchmake with. It's a 7 month season so you've loads of time to level up before you decide. Edit: all this is in lighffall deluxe, I believe there's an upgrade on steam, but not on console, & i see you're on epic so you'll have to see if it has an upgrade option. Again you can buy it much cheaper from somewhere like cdkeys or cjs-cdkeys, but I don't know how epic work so again you'll have to look at that. Final shape deluxe is content from June 2024 to potentially June 2025

e.g. Would we need to buy the lightfall season pass? Or the final shape season pass? It would be handy to know which seasons were in which season pass...but I can't find out how to look.