I see the question of editing m3u lists come up a lot in this sub and often the answer is xtreme-editor which is a fine choice (I subscribed myself). There are other options of course but one that is somewhat overlooked a bit primarily because it's primary purpose is to emulate the HDHomerun device to allow IPTV to be used with Plex.
xTeVe is primarily an emulator but it also has a very good m3u editor and it is free to use and as a bonus for all you Plex users, it allows IPTV to be used in Plex. The only downside is that you must have it running somewhere on your LAN. I have it running in a linux VM and it works great.
Here are a few screenshots.
https://imgur.com/a/Ijp8uQk
I use this one https://m3u4u.com it is free and also it has EPG.