Like others, I highly recommend modpacks. My friends and I were playing on a server with one of the more recent Direwolf packs and it really reignited my interest in the game. They add content that rewards you for progression and adds ways to earn quality of life improvements.

For example, you can make a series of machines that break down and refine raw ores to multiply the yield from raw ingots but require power. Power can be harnessed in the same ways as real life, but I used a method that used fuel made from organic food mixed with hydrogen, which was gathered from electrolysis. The oxygen I used for scuba tanks to explore the oceans, and excess hydrogen became fuel for a jetpack that made navigation much more fun. And there's things like freeriders that prevent fall damage (at the cost of durability) and allow auto-stepping over one block elevations, which doesn't sound like much but is so nice that I find I can no longer play Minecraft without it.

You could make mining lasers that use power to break down blocks quickly and can be upgraded to target more blocks at once, be more efficient, auto-collect blocks, have silk touch, etc. Upgradable portable storage and backpacks also let you keep anything that might be useful on hand, and could do other things like play music or auto-feed you from stored food. There were other simple quality of life things like graves that kept your inventory stored where you died (and marked it on the map, and even put the items back in your inventory in their original places), a craftable experience bank, saws to cut down trees quickly, waystones that let you fast-travel, etc.

There were also several magic systems that let you do things like cast magic bolts, heal yourself, repair durability, tame supernatural creatures, transmute materials, create portals between locations, and lots of other things. I made a custom spell that let me super-jump so I could catapult across continents and was mostly limited by the speed that chunks could render. This of course had its own progression system to prevent trivializing other parts of the game.

There's a lot more that I didn't get into, like plenty of new mobs (that usually also had lore), bosses, storylines, frankly amazing structures that spawned radomly, new dimensions, equippabled artifacts, and new planets accessible by creating rockets. One of my friends made a colony of villagers to handle resource gathering and even base-expanding, while another created a nuclear power plant that at one point leaked and irradiated essentially the whole continent for days, excluding people who had rad suits. It was much more fun than I've ever had in vanilla, and there's plenty we didn't even explore.