Free RTMP client Android app

All video platforms, Youtube, Facebook, Twitch, etc. offer RTMP server url + token that can be inserted into the streaming client to create a live stream. This is a slightly more flexible way that bypasses restrictions, e.g. through the Facebook app by default, your stream is uploaded to Reels (which you may not want), while the Youtube app for live streaming requires 50 subscribers, etc. With RTMP url, that's not the case. On your computer, you have free, open source OBS, but on Android (phones) there are no such mature and free applications. For example, there is Larix Broadcaster which gives a large red watermark over the entire screen for free, and it's not cheap at 10 euros per month, there is Prism which also has a watermark and a lot of limitations and bloat, Streamlabs again has one stream and ads, etc. Is there a mature, free, open-source application for Android for this purpose, an RTMP streaming client?