I tried mazes in sessions, but it always felt a bit arbitrary as they would just say “we hug the left wall”. Was the maze shifting? How was it describes?

the maze was not shifting, but it also wasn't a true maze in the sense that there was one continuous wall with no gaps. (IE following a single wall would lead to walking the same loop.) The maze's gaps were constructed such that doing so would keep you in whatever ring you were in.

the maze itself was static, but that didn't really matter cuz they suck at making their own maps. (or note taking in general. I record the audio of each session and give them speech-to-text transcripts that they never look at unless I give them a very good reason to.)

The maze was essentially broken into rooms (even if I described it as a continuous hallway,) Each section of the maze constituting we use oldschool dungeon turns for non-combat (which is about ten minutes) when exploring dungeons, and each section is the area they can technically cover in a single dungeon turn.

Theres a few general actions they could take-

1. explore.
2. pass through.
3. rest.
4. combat.

exploring might come up with loot of some type- health potions, useful items. maybe gold (which could be used at the start of the next session for better starting gear.) or scrolls and stuff. Maybe they find interesting wayfinding symbols that lead them into traps. (yeah. I'm not that nice. There's no treasure without risk.) (mostly there isn't treasure.)

Passing through gets you into the next section.

resting got a bit wonky and needed some tweaking between sessions, but it was a very short rest- dungeon turns are about ten minutes of in-game time where a short rest is about 1 hour and a long rest is at least 8 hours. we essentially settled on getting 2 actions/spellslots that would reset on short rest, or one long-rest spell slot instead.

Combat is, well. self explanatory, except we used some 'expedited' combat turns. It was very fast paced combat so we didn't get too bogged down in it. (the murder hobo loved this.) Because it was basically one player against my cohort of NPCs, so there didn't need to be a lot of conversation or table talk. it was easy to keep the dice rolling, so to speak.

it needs to also be said that there different things that could trigger a combat. the center of the labyrinth was a boss that was ultimately unbeatable. (though the bard made the best go of it, managing to seduce the poisonous plague slime... he died from around 36 new and interesting diseases and 28 different kinds of poison.)

there were the roving patrols that were moving along a path I could see (and there was an awareness check whenever they got close to the PC. the roving patrols were actually the most dangerous, largely because they would come in as you were finishing up the last combat and such like. These were the gladiators (complete with the excessive muscles, spandex and sock-improved mooseknuckles. we're never going to forget the moment the Murder Hobo asked why they always had an extra pair of socks...)

the goal, is to keep moving and stay away from the roving pats, trigger enough combat rounds that you kept yourself up in gear, rest enough to keep your action economy viable and do everything in your power to stay out of the center room. And then there were the random encounters.

Hoe did the randomness of the labyrinth work?

so, to preface this, they didn't know how the mechanics worked at the start. they had sending stones that characters could use to talk to other characters- and incidentally the gladiators, some of whom were in with them. Not that they knew they were gladiators... they presented themselves initially as other contestants. During rests and exploration, they would be free to talk with whoever. If they said something 'I just passed an ugly sphinx statue!', the gladiators would, for example, know where they were and try to find them. the gladiators would, on occasion tell them things. give them advice. (sometimes, it was even good advice.)

they had to build their map as they went, and they could only see the current status of the section they were in, and the roving patrols were liable to move traps around just for the fun of it.

each dungeon turn, I would roll an encounter check. a nat 1 would trigger an encounter. the outer-most ring would use a d20. then inwards from there, a d12, d8, d6, d4 and d2. if nat1 was rolled, then I would roll a d20 with a list of potential encounters. (this was described as being portalled into the labyrinth on top of them.) if, lets say we had a sixteen and they had already had that encounter, they'd go down the list until an encounter they hadn't had. If they were clear through to 20, it comes back to the start. if they had 20 encounters.

Each encounter was difficult enough that not using spell slots liberally was a risk. If you went past 10 turns, the gladiators would hear the fighting and come towards you. All. of the gladiators, except the center boss room.

the goal was to survive each sessions as long as possible, winning entailed being the last one standing.

as far as how I actually described the labrynth itself, the walls were largely uniform, though there might be the occasional pictograms or wayfinding markers or other puzzles for them to play with. (including a few that were just there to waste time. like giant rotary abacuses, or one that was described as a caledescope that you'd have to look into and align the gaps. it would then tattoo "idiot" on their forehead one letter at a time. those were 'align the disk' like puzzles they got to work on, on their own.)

the floor changed, on occasion, from being 'sandy' to some kind of flagstone, to tiled mosaics, to quick sand. the walls were tall enough to avoid letting them misty step or whatever out.