As a new player, I feel out of place in the story because of the level of exclusivity of old content

I just started playing a little over a 3 weeks ago, am already in Sumeru, and, while the gameplay is intuitive enough, I stuggle to feel included in the story aspect of the characters, mainly because things that helped expand them are no longer avaliable to me. For example, one of the very first characters you play with is Kaeya, and while his story with Diluc is alluded to in their profiles and in quests, the only questline that actually adresses what happened between them exactly is an event exclusive one from 2021, which as of right now is forever unplayable, just like other character focused events.

Plus, many characters that appear in the beggining storylines and that begginer players are actually familiar with,are now extremely difficult to acquire, since they're either locked behind infrequent banners or drowned by other 5 starts on standard, and it all makes me feel a little bitter. It feels like punishment towards players that didn't have the foresight to start playing since day one, and it's also frustrating to have such a big experience gap between players that happened to witness an event and players who missed it forever.