TCL S405 is an inexpensive, low latency 4K TV that works with x2, x3, x4 and x5, including the SNES, as well as 480i x2 and x4, 288p x2, 576i x2, and 480 x2. It didn’t seem to like
480i or 240p passthrough but worked fine with pretty much everything else. I’ve heard the more expensive TCL P607 works similarly, but I cannot confirm this.
UPDATE: I was able to get 480i passthrough working by setting TX mode to HDMI. 240p passthrough still displays at the incorrect aspect ratio, though. Also keep in mind that lag increases on this TV for interlace sources, even in game mode.