Displaying Web Videos

Apologies for this only partially being an AlmaLinux topic, but I’ve been struggling with this for over a week and not making any progress. But not sure where else to begin.
Have a personal web server, AlmaLinux 9.4 but can’t figure out how to get videos to display in a web browser. There are multiple parts to this.
The videos (about 250) are all from personal video cameras. Some need to be split up, some need to be concatenated. I’ve been using ffmpeg with mixed results and can’t seem to find the one single magic solution.
First, the most current of ffmpeg behaves differently on Linux and Windows. Options accepted on Windows aren’t accepted on Linux. Also, Linux version barfs unexpectedly when Windows doesn’t. Very frustration.
I’d really like to find somebody I can work with off-line to help me with options. I’m way over my head with containers and codecs. I can split and concatenate, and VLC plays the videos perfectly. However EVERY conversion to a web-supported format results in noticeable loss of quality.
Anyone feel like holding my hand through this? I fear I’m making the problem more complicated than it really is.