Tvheadend

Hi, I'm new to this and trying to figure out the best way to be able to use my IPTV service the way that I want to. I don't want to load all the channels from my IPTV service because it takes a very long time and I have no use for that many channels. What I would like to be able to do is filter out all the channels I wouldn't use from the m3u playlist before loading it into tvheadend so that it will only scan the channels that I want. Ideally this would be an app that ran in docker and updated periodically so that my stream URLs would always be up to date. I haven't been able to find something that does this that is hosted on docker hub and has good documentation that I can understand easily though.

Another option I thought I could take would be to download the m3u from the URL, edit out the channels I didn't want and then load that file into tvheadend. The problem with that approach though is that I would have to embed my credentials into each URL in the playlist to get it to work. Is there a way to load muxes from an m3u or perhaps use a local m3u to create the network and then assign the found muxes to a different network? Is there a generally considered best practice for this type of thing?