Pretty much anytime they mention “catalog”, PS+ essencial doesn’t have access to it. You guys only get the monthly PS+ games, which stay up for grabs for 30 days (but you can play after that if you grab ’em in that month).
Extra and premium get the monthly games yoo but their main advantave is acces to the catalog, a list of PS4 and PS5 games that stays open to these subscribers to download and play for however long they stay there (some stayed for about 6 months, some never leave, it’s a case by case thing), it’s just a much bigger pool of games available for “free” than essential. Truer to a subscription service though, if games are removed from the catalog you can’t play it anymore unless you purchase it, while the monthly games are “yours” as long as you have any PS+ membership active.
Premium/Deluxe also get a unique section of the catalog for classics that PS+ Extra don’t have, with games from past older genetations. The difference between these two is the streaming service isn’t available in some regions and since there isn’t PS3 emulation still, Deluxe miss out on PS3 games on the classics front. I don’t think they are ever both offered in the same region though, so what you see on your local store is what’s available there.
There’s also the “Instant Game Collection” or ICG, it’s like a mini catalog, it’s a list of games that stay available for all PS+ members to grab whenever they feel like, but it’s only like a dozen games long (against the multiple hundreds on the real Catalog), it doesn’t get updated monthly but rather it was a list of games to entice PS5 new owners on release, I think maybe a couple games ever got added to it… In fact I believe it’s only available on the PS5 storefront still but I may be wrong there.