Tips for someone picking up the game after a few years?

I don't like giving advice, mainly because I feel like I'm imposing something on someone, but I do think I have some nice tips to share this time.
I assume you are playing on the latest version (1.16.5 on Java Edition, or some other version on Windows 10 Edition). The current versions of Minecraft are well-developed, so sometimes you don't really know where to start. I'd recommend you explore Nether. Netherite - the new best resource in the game - was added in update 1.16. You can make the best tools and armor out of it. Netherite spawns in - well, Nether - mostly in the Y-axis of 8-22. You also need a diamond pickaxe to mine it.
Apart from that, I also recommend you visiting a Woodland Mansion. You can find quite valuable loot there, and you can trade for the map from a villager cartographer who is on the apprentice level.
Additionally, if you don't have them yet, I would recommend you getting Totems of Undying. They give you a "second life" after you die and a few effects that will surely help you in the fight against tougher mobs or bosses. Totems of Undying drop from Evokers - Illagers, which spawn in woodland mansions and raids, which can occur when you enter a village with Bad Omen effect after killing a Pillager with a banner on his back.
Sorry for such a long answer, but I don't know how can I shorten it. Generally - have fun.