Asklemmy

There are very good mobile games without subscriptions, virtual coins, loot boxes and shit. Some examples on iOS:

• Sawblades
• Ollies Arcade
• Knotwords
• High Rise

Buy a pack of sticky notes and a pen and let your imagination go. Write weird facts and trivia, or just whatever you want and stick 'em in places where people are gonna look, like on maps, mirrors, napkin holders at the bar...
Then just wait and watch

Try Monument Valley it's a one time pay puzzle game that moves like an MC Escher sketch.

I know you mentioned audiobooks but what about some digital books? Personally, reading makes my eyes tired so I know that, for me, reading something would be a good way to provoke a nap.

As a response to the idea that you may get fatigued by passive media, a book may be a good balance to that. With movies, shows, and audiobooks, you're going to be listening the whole time. It's just constant noise. A book may be more meditative.

Which reminds me, this may be a good time to practice meditation.

I wouldn't get wasted, if you're in your 30s that can give your worst headache ever. If the wifi is good enough, maybe start a series? Possibly something with short episodes, a well-selected anime will easily kill something like 10 hours. And if possible, try to get as much sleep as possible

No advice, but I sympathize. I once sat listening to music while waiting for my flight to board. When there was no activity and fewer passengers in the area than I expected, I discovered that while I had been waiting they changed the gate for my flight. I ended up waiting in Chicago Midway (this was before their big upgrades in the early 00s) for 12 hours. It was hell.

It may sound stupid, but try learning some card tricks or play solitaire with some playing cards?

Do you like Roguelikes? Slay the Spire is really good and it's on Mobile.
It's a port from PC, so no microtransactions or garbage like that, one purchase and done.
There's also Mindustry. It's a mix between Tower Defense and Factory game. This one also has no MTX since it is a Open Source game. Free on Android, 2 Bucks on iOS.

Twist your thumbs

As for android games, if you're into tower defense, give infinitode a try :)

It's a damn shame that you can't go to a pharmacy in the airport, tell this tale, and get some xanex to zonk out and time travel to your destination.

Vampire survivors and random lore vids.

Unsure of your preferences with games, but Shattered Pixel Dungeon is free, offline, no ads, and the only purchases are for aesthetics to support the app. It's an 8-bit rogue like, and never the same game twice.

I highly recommend emulating games on your phone. Some of them aren't great without a controller but its worth a shot.

Puzzle books? I like to play with variety puzzle books, commonly sold near magazines :3 Crosswords (and varieties thereof), word searches (+varieties), crypto puzzles of various sorts, number puzzles of various sorts, the funky neat ones where some of the words share some letters (like, a letter fills a vertical region to be shared by one or more words), uhhh... oh also I like to write the solutions in Thorass :D https://forgottenrealms.fandom.com/wiki/Thorass_alphabet Though the numerals are garbage. D'ni numerals are far, far better 👍

Also, I daydream for hours at a time. ... But probably you don't or else you wouldn't be asking for ideas I guess 😅

If its your thing try kearning a language on Duolingo or something like that

The Lahey link made me laugh way to hard, I've been sick as fuck the last 2 days and I'm laying on the couch watching trailer Park boys with a decent buzz so it's fitting.

It's not gonna last you 20 hours, but last I checked the official Sonic 1, 2 and CD ports are all free on mobile (and they're really good).

Bloons Tower Defense 6 is a really good game that you could sink time into! It is paid, but I highly recommend it

Have a 2 hour phone chat (with spouse?)

Buy a note book and write a diary to remind yourself of everything that has happened in the last year.