Hosting is cheap and there is free hosting available if you don’t care about having a custom domain and have a limited audience. If your audience is big enough to go past that bandwidth you can probably monetize somehow and cover server costs easily, even if it’s just selling a few pieces of merch. My website is $80 a year with a custom domain and I get unlimited transfer/bandwidth. It’s shared hosting so over about 1k visitors per day means it’ll get slow but if you’re getting that kind of traffic you can probably sell more merch and get a vps

Use twitter/pixiv/ig for promotion but if you don’t do the above your locking out anyone who refuses to make account. All of them won’t let you look at more than 1-5 images before locking you out entirely with account nag screens that can’t be bypassed. Or just stay on those platforms, I don’t care, I’ll just never read your comic