The same setup works when connected to a PC Monitor via HDMI.
Hi, to simplify that "EDID" story. The EDID data is a small amount of data written usually in a small memory chip in the display. This data "explain" the display what type of image can handle. If with same video source (your RPi4B) and HDMI cable, another display working (and in the Kodi display settings do you see few different resolutions), the EDID issue (if exist) probably is in that "Toyota Sienna display". Even for this could be a workaround. If that display support any kind of "standard" resolution (you mentioned the 1280x720), check if your another (working) display have the same mode available. If yes, connect the "working" display, run in SSH the "getedid create" command, set the resolution to be compatible to the "Toyota" display and try it. If you ar lucky, and till the resolution will remain unchanged (should use the video mode white list to enable only that) you will be able to use it.
And why sometimes the diplay "working" even without EDID data? That depend on how is programmed the video source device to handle the missing EDID, maybe will provide a low, standard resolution (and most of the displays will display something) or just disable the output...