Thanks @clude - in particular for finding the package for edid-decode. I agree it’s probably no big deal that grab-logs can’t find it - I only thought it possible that the rest of the system might seek to use it, and its absence could actually be causing my issue.
Re disp_cap - yes, I’ve been fiddling with that in the past (Interlaced output to progressive-only display? - #5 by qpkorr ) - and when I reduced mine to just 1080p60hz, everything worked, until now.
Re an earlier tip above, I did also trying blowing away my .kodi directory and rebooting, but that didn’t help (in case unsupported plugins were the issue).