I am using plex on my local LAN on my phone, web browser, TV’s etc.
I find watching plex via my TV works perfectly, yet when streaming via my web browser on my same wifi network is horrid… it keeps showing the loading symbol every 30seconds or so like its caching and it can do that for up to 5min a time.
By TVs are not he same network and even the same room with no issues
Use Plex for Windows/Mac. It is a more robust client than Plex Web, direct playing most video & audio formats.
Web browsers have limited audio/video codec support. As a result, Plex often has to transcode the video or audio when viewing via Plex Web. This can result in buffering if your server cannot transcode in real time.