I tried to export trial of the sorcerer but I had some errors one of them was that when I tried to start the first level of the game it said download failed and I couldn't start the first level,
another error was runtime error params a nil value in initlevel line 268 (tab 0)
or something?

I really don't know wether if this game can be exported or not. I just want to play it offline when wi-fi isn't around that way I won't use up a hotspot or mobile data.

I'd guess that the game involves multiple carts running each other. I suggest looking up how to export multiple carts together, as there is a way.

That game is a multi-cart game, so to successfully export it, you would need all the cart files that make up the game. Nerdy Teachers did a writeup of this here: https://nerdyteachers.com/PICO-8/Guide/?EXPORT_MULTICART.

I'm not sure if this is universal, but on my machine all the SPLORE carts end up in .lexaloffle/pico-8/bbs/carts. I suppose to successfully HTML export the full game, you'd need to play in SPLORE enough to get every cart file then export them all as described in that link.