Before you start flashing new versions of firmware entirely which could potentially come with new problems as well, have you at least tried clearing the app cache for the 2 problematic apps you've mentioned and/or the system cache? (Apps can sometimes degrade in performance over time, especially apps that heavily rely on caching data such as Kodi etc. If you're also running unofficial add-ons or you're using builds (which cannot be discussed here), then they too could cause any number of problems, builds especially. So avoid anything unofficial & try a fresh install or a clean Kodi.)
Have you also tried clearing the app data if clearing caches fails too? Otherwise, have you tried factory resetting your existing firmware for a completely fresh start rather than flashing a completely different ROM which may not be necessary at all?
Have you also checked your existing version of Netflix? (Details here of current working version 6.26.1......
https://theminixforum.com/index.php?threads/problems-with-netflix.2290/ and https://theminixforum.com/index.php?threads/minix-u9-h-netflix-hd.2803/#post-23514
If you're referring to the flashing procedure to actually install the CE ROM, then a Windows PC is essential there too.
Although, you could also try the burn card maker method which is known to function successfully with a U9-H too. (Just follow these instructions but obviously download the firmware image for the U9-H.....
https://theminixforum.com/index.php...pop-firmware-update-with-burn-card-maker.234/ .)