Our group did a two-part Microscope-like after a "season" of 14 sessions to wrap up a ton of loose ends and set up the next season. It was super satisfying to zoom in on only what the players wanted to see and resolve.

Our first session of January is going to be another Microscope session too, we've got a giant pointcrawl to backtrack and see the fallout of our action or inaction.

Holly shit, that's badass

Which edition are you playing? From what I can find, the Epic Level Handbook was 3e.

For people playing 5e, yeah, the game just breaks down around level 13-15. One of the funny things is that WotC has clearly recognized this is a problem, because they've implemented a solution... which is to just not publish high-level material. They just gave up on it.

If it were me, I'd find it easier to change the lore so you can do planar exploration at lower levels than to deal with all the mechanics and balancing of level 20 characters

Yep same. 2.5 years. It was a blast. Some of the best times with my friends ive had.

It's not actually that much to learn when you realize that the core rules are pretty simple, and all of the rules are pretty much just suggestions to help you wing it.

I've brought players into my games before who know literally nothing about it and they just figure it out on the fly.

DMing is a little more demanding, but it's the same deal: You just need to know the basics, and then you mostly wing it.

It's not really that hard if you're actually passionate and interested in it. There's lots of resources out there for finding groups. And especially now, if you're willing to play online using a virtual tabletop, it's easier than ever.

It's actually not that hard! There's only a handful of core rules to know for every session and the rest you can learn as you go.

Attacks and spell attacks: 1d20+prof (proficiency bonus)+ability+special bonuses (items, buffs, etc)
Ability checks: 1d20+ability. If it's a skill check you have proficiency in, add +prof.
Saving throws: 1d20+ability, +prof if you're proficient in that saving throw.
Note: all of these bonuses are summed up on your character sheet under your spellcasting page, your weapons, skill lists and saving throw lists.

In encounters you can do the following: Action (extra attack included in 1 action), Bonus Action, Reaction, Movement, Item Interaction, and any number of Free Actions.

DCs for figuring out how hard something easy:
5: very easy, most people can do this most of the time
10: easy, people trained can reliably do this
15: medium, decent odds if skilled
20: hard, rare success unless very skilled
25: very hard, rare success even with highly skilled
30: nearly impossible, heroic aptitude still fails most of the time
35: godly, the highest DC likely to see. impossible without epic amounts of skill and even then very unlikely. even demigods may fail

D&D is hard. Sure the core of it is straight forward but then things start to add up. It is a game that wants you to care about minutia. How far travelled, distance between two points, the height of dungeons ceilings, how long passed since that spell was cast, how much you ate yesterday. And it wants you to arbitrate spell interactions, players weird schemes and prepare a lot of stuff. Also it wants you to actually run the narrative. Some love this difficulty, find the intricacies challenging and desire to master it all.

The good news is that the behemoth of D&D isn't alone out there. Really lots of good stuff can be found. First problem is knowing what one want to find. Second is finding others that have similar taste to you. But it is doable and a good thing to do is ask for help. Because if it is something we like here it is to talk about ttrpgs. Getting us to shut up... better ask santa for a dragon.