vdo ninja - phone to OBS

https://vdo.ninja/

• 100% free; no downloads; no personal data collection; no sign-in
• Bring live video from your smartphone, remote computer, or friends directly into OBS or other studio software.
• We use cutting edge Peer-to-Peer forwarding technology that offers privacy and ultra-low latency

not exactly clear to me how to use, but I haven't used OBS in quite a while