how to mark difficulty of trails (highway=path) for motorbike specifically dual-sport ?

For instance in Northern Thailand, single tracks (highway=path) can be either:

• A) steep mountainous trails with hard bends, cliffs, rocks/roots and used by locals on foot only. Only very skilled enduro riders with lightweight dirt bikes can attempt these.
• B) flat or hilly terrain along rivers, lakes, fields, and forests: locals can navigate these on a small motorcycle, so perfect for any MTB or dual-sport motorbikes.

Since I focus only on B) and want to avoid A) when scouting and planning itineraries, I am looking for a way to tag these trails (highway=path) so they are rendered differently.

• tracktype is only relevant for highway=track and to describe its softness
• smoothness is good to describe the required clearance but not the steepness/tight bends requiring potentially pivot turns
• highway=footway to describe A) would be ideal but I believe this tag should be used instead in urban areas

Additional came across this proposal https://wiki.openstreetmap.org/wiki/Proposed_features/motorcycle:scale I like the idea of a rating system however not the fact that this would require some separate viewer.

Any ideas on how this could be solved? Thanks!