I’m somewhat a connoisseur of cheap TVs it seems:
Bauhn ATV58UHDC (the 58″ Aldi 4k special with a bundled Chromecast in Australia)
SNES (NTSC+PAL) works with all modes. Line5x is sharpest, but severely crops the picture, so I use Line4x and force the TV to 4:3 aspect for what I think is the best picture. Audio works fine, including 96KHz sample rate.
NTSC SNES, PAL PS1 (modded) playing PAL+NTSC games, everything works great, absolutely beyond stoked. Haven’t tested my PAL SNES yet because I lack the correct SCART cable for it.
SNES (NTSC) with line-triple seems to work fine, not happy with any of the higher modes though. Only works on DVI mode, HDMI results in no signal (even on the test pattern), though I didn’t play with it much maybe it’s possible to get it to sync. Obviously no audio in DVI mode.