I would recommend focusing on lore heavy stuff then adventures.What would be your top recommendations then for someone that started playing when 3E came out?
So campaign settings and monster books are often evocative and I have referred to them in my 3e-5e games.
2e Monster books spent a lot of text on descriptions in the main monster books so you get more to work with than stats and art. 3e was a real step down for that. I'd recommend the monstrous compendium appendices in particular for themed collections. Until the end of May the D&D and Monsters of the Guildverse sales overlap a bit for double discounts on some D&D monster books so now is a great time to grab a bunch.
I am a big fan of the original 2e Ravenloft campaign setting for gothic horror D&D. Great advice for DMing and a cool setting. 5e has a version that is just isolated realms, 2e started off with a whole setting where there was politics between realms and darklords.