Digital comics, any alternative to Amazon?

I live in rural NM, and getting physical comics is a trek. I used to use Comixology, but missed physical books so much I opened a comic and game shop in my small town. The comic side of things failed, my game sales were financing the comics. So after just over a year i cancelled my comic account to focus on the games.

Since then Amazon took over comixology and moved shopping for comics onto Amazon, which after three days of trying to find titles I have decided to explore other avenues.

I know when I was selling comic books marvel had their own app, do all of the publishers have those? Or is Amazon the only name in the game?

I am looking to catch up on Dynamite’s Red Sonya, Marvel’s Conan, Elfquest, anything X-Force, X-23, and probably Firefly. I have not read a comic since my last order came into the shop in January 2020. The news of the new X-23 series is what started to pull me back in again, I did manage to get a subscription to that on Amazon.