Only anecdata. But this is experience from using 4oD and All4 with comparison to iPlayer for the last 12 years.
The problems described above were so bad on Roku that I had a '3 strike' policy - if the stream failed 3 times in one sitting and forced me to start the show again and sit through ads then I'd leave All4 and watch another service. Three strikes would be met weekly.
I contacted support on multiple occasions but they weren't helpful.
I haven't had anywhere near the same experience, even using self hosted like Plex and Jellyfin.
The problems described above were so bad on Roku that I had a '3 strike' policy - if the stream failed 3 times in one sitting and forced me to start the show again and sit through ads then I'd leave All4 and watch another service. Three strikes would be met weekly.
I contacted support on multiple occasions but they weren't helpful.
I haven't had anywhere near the same experience, even using self hosted like Plex and Jellyfin.