VLC. And on ancient Androids, MX Player. That one I use on my Samsung GT-S5830i (Android 2.3.6). I think the Android VLC may even be able to play ripped .iso files but I haven't tried that yet. I'll try ripping some smaller DVD and I'll report back to you.
I have been using VLC on linux and android since forever, but recently on my new Amazon Firestick 4k Max, VLC was having issues playing h.265 HEVC movies. So, someone recommended Nova Player, and it played them beautifully. Nice player, I may switch all my devices to Nova.
I prefer MX Player with custom codecs for most videos due to its comprehensive features and quality of life customization options, for HEVC HDR videos I use mpv as it's one of the few players capable of displaying them properly on my phone.
For music, I use Neutron because I'm an audiophile