Have you ever tried hosting it in an actual web hosting site if it works? I was thinking if that was possible, but I think it should be. What I mean is having all the working files transferred via FileZilla for example, to a free webhosting site.
I have been successful, yes. Uploaded it to
RPG Maker Times MV Fun, which is specifically a test site for live testing. You probably won't have much luck with many free sites, as they mostly tend to have their own limitations. I've heard that
Google Drive can be used to upload and play a game, but I've not tried that.
GitHub as well maybe, with a bit of tweaking. It all depends on other things, like whether the free (shared) hosts can handle or allow high traffic/bandwidth.
I'm hosting the entire
RPG Maker Times (blog and subdomains) on Dreamhost, which does allow direct FTP transfer. The reason I eventually upgraded was because, with a lot of these free sites, most of them are shared servers so playtesting uploaded MV games often resulted in frequent downtime due to exceeded bandwidth and server stress. FTP uploading apparently contributes towards this, so larger files (ZIPped or otherwise) tend to eat away at it, putting on that weight and stress oftentimes. Only because it WAS a shared server. I haven't regretted upgrading to a dedicated server.
You can use Firefox or Avant for testing MV games locally or online if they're "raw". Many sites like the aforementioned itch.io or Kongregate work with ZIPped uploads, but tend to err with larger filesizes.