I'm not challenging your choice to map the footpath as a separate way. I respect that your approach is one of several acceptable approaches.

1. I don't see why OSM cannot accommodate mapping for both vulnerable and non-vulnerable classes of footpath users.

If you feel that a connection which somebody added between a footpath and road is unsafe for use by a subset of footpath users, then the solution is to tag it as such, rather than delete it.

I imagine that tags such as https://wiki.openstreetmap.org/wiki/Key:wheelchair and https://wiki.openstreetmap.org/wiki/Key:tactile_paving and https://wiki.openstreetmap.org/wiki/Key:kerb and https://wiki.openstreetmap.org/wiki/Key:lit would be useful when it comes to placing importance on the safety of vulnerable users?

For example if you deem an otherwise valid connection that somebody added unsafe to use because it involves a raised kerb, the solution is to map the raised kerb rather than deleting the connection.

2. In the example journeys I gave, there are crossings (with dished kerbs too) at the t-junctions of roads along the route (see See https://www.openstreetmap.org/node/10754018268 and https://www.openstreetmap.org/node/10754018234 for example of such locations), but you neglected to connect your footpath with the road at those locations.

It is when connections such as https://www.openstreetmap.org/way/1180320076 are deleted that the separately mapped footpaths become the only option for the router. Consequently, if the separately mapped footpath isn't connected to the road at the applicable pedestrian crossing points along the way, we end up with these convoluted pedestrian navigation routes.

Have a good night.