I guess my question comes down to “should the sidewalk be considered missing if the road have a dedicated footway near?”.

I not an experienced mapper and to be honest don’t really understand the purpose of a sidewalk tag on a road with a dedicated footway mapped close to it. According to the wiki the main advantage of the sidewalk tag on a road over the dedicated footway is routing by the road name. But wouldn’t the dedicated footway be preferred for routing over the road with a sidewalk tag if both are present thus eliminating this advantage? What is the purpose of tagging the roads then?

Why are you only considering sidewalk tag on the road itself but not a separate way with highway=footway + footway=sidewalk combination? Is there a reason to prefer former to the latter?