One of the things you can do is get a proper iptv provider. However most of them have literally thousands of channels that are entirely irrelevant to what you want and also Jellyfin will choke on having that many channels added (ask me how I know).
One of the things you can do is use Dispatcharr to manage your iptv channels and act as a middleman. You can do things like only add channels from the sports group to it and that will give you a manageable number of channels to pass to Jellyfin. You can also experiment with other tools that you can find in the Dispatcharr Discord to do things like automatically create a list of all of today's sports events, create channels automatically for each event, create a group of all the games for today's NFL games, etc... Dispatcharr will provide an m3u file you can give to Jellyfin.