I never did any paid advertising. At this point it's roughly 80% organic algorithmic platform trafic and 20% word-of-mouth. The latter includes outside user-driven platforms, like MiniReview and TapTap.
I used to do guerilla marketting a bunch, mostly on Reddit, certainly a lot before and around release. I got some ok youtuber and streamer coverage around this time. Ended up releasing on Steam with 10k wishlists, which was enough to provide an initial visibility boost.
Soon before releasing on mobile, I participated in the Humble Stand with Ukraine Bundle, where I distributed 200k+ free keys for charity. Marketing value wasn't what was on my mind at the time, but I know quite a lot of people who picked up the bundle tried out the game, thought "neat but I'd prefer to play this on mobile", and then helped to drive a lot of initial traffic and get picked up by the algo.
I also got featured a bunch in both Google's an Apple's curated game collections.
https://j4nw.com/pawnbarian
I feel doubly blessed that it worked out with no ads or micropayment sinks of any sort, just a demo and a single $5 purchase.