Help getting lossless movies to stream

So I have been running Jellyfin for about a month now through a Docker container in my UGREEN NAS. I have a reverse proxy with Nginx Proxy Manager and DuckDNS set up, which works fine. The only part of my library, which is a variety of DVD, Blu-ray, and 4K rips, is completely lossless excluding I do extract the Dolby Vision Profile 7 from 4K Blu-rays that have them. Whenever I stream from my phone (Galaxy S24 Ultra), anything with higher quality than a DVD takes forever to load and does not play very well while on mobile data or a bad wifi network. Many times, there is no chance of getting a 4K movie to stream. I have tried different Jellyfin for Android clients, which seem to work better but still have a lot of problems, taking a long time to load and having the movie freeze up a lot, especially if it is a 4K rip. I feel like I have tried a lot of things and do not know if this is even realistic or feasible, but I feel like I have heard of others doing it, so I am asking if I am missing anything crucial or important.