I got really upset when i should update my local M3u file and then clean out the old one... EVERY time i get stuck on 10% and have to SSH to reboot the system.
1. Deactivate IPTV Simple PVR Client Addon.
2. Change to the new m3u.
3. Now go ahead and clean out the old m3u.
4. Go back to IPTV Simple PVR Client Addon and activate it.
Wait a couple of seconds and it will start to load the new m3u..
This is the only way for me after the update to Kodi 19.3 on my RPi 4B 4gb... I do not know if that is a bug or something else...
/Thore from Sweden