mainstream providers like onesignal are a waste of time for adult projects . they’ll let u collect subs for a week and then nuke the account the second their automated filters or manual review teams spot a thumbnail
u should look into propush . it’s a sub-brand of propellerads so they are 100% adult-friendly . the best part is u don't just get the push tech , u actually get paid for every sub u acquire . it’s basically an extra monetization layer that helps with returning traffic signals at the same time
if u want total control and zero risk of being deplatformed , u gotta reconsider firebase or a self-hosted script . i know u said it’s a pain to set up , but owning ur own .js service worker is the only way to guarantee those subscribers dont vanish when a saas company changes their tos . there are plenty of ready-to-go service worker templates on github that handle the browser handshake without the heavy middleware
another one worth checking is pushwelcome . they are way more lenient with niches compared to webpushr or onesignal and have a solid free tier to get u started
bottom line : in the adult game , if ur not using a provider that specifically handles high-risk traffic , ur just building ur audience on a foundation of sand . stick to the networks that actually want ur traffic