There are services (intended for travelers I think) that sell pre-paid SIMs and maybe even ESIMs, which might be non-kyc or circumventably kyc (aka buy a visa prepaid with cash, use it to buy the esim, provide fake name and address, etc etc etc)
There is also jmp.chat. They provide a non-kyc ESIM or SIM (no idea how they deliver it non-kyc, I don't use physical SIMs) with something like 6 or 7 USD per Gb, which sounds steep. However, I've had good customer service support with them via their Cheogram (their app) chatroom.
... There is also silent.link... Which can be paid for with BTC, Lightning, or Monero. Their rates in the US are usually far cheaper (except in Alaska holy crap), but you'll have to check their rates in your country on their website. However, I personally had a singularly atrocious experience with them, and personally do not recommend giving them more than the absolute minimum money you need to give them to top off your ESIM, and never more money than you can afford to lose.
There's another one that I can't remember, but it had some cons of its own, and it was also a bit pricy
JMP and silent.link both work by giving you an ESIM (or SIM, maybe, if JMP) that can use each carrier's roaming towers/networks, just not the main local ones, to provide data.
This still means you can be triangulated and your location correlated with addresses and other stuff
But it definitely takes a significant bite out of the level of privacy invasion going in when using mobile carriers. How big is that significant bite? No clue. I'm not that smart or educated or experienced. But it's definitely something, not nothing.