I just threw my ONN 55” tv away today. Have had the same issue as you since 6/2024. No answer, no solution and SOL. Sorry about your situation but it seems to have been an issue since 2023. My advice is trash it and buy a different brand it’s a shame Roku just doesn’t care
It's single device at a time restoration and takes days for ROKU devices to be fixed. Seen several of the TV's eventually updated. Took couple weeks for my streambar and few days for stick. As long as this has been going on it's surprising they have survived.