Garmin BaseCamp lets you somewhat plot routes that way by messing with the "average speed" settings but it's really a hack and doesn't work great. The software has a bit of a learning curve to use and the map detail is lacking. Garmin stopped developing the BaseCamp application several years ago, so it's not receiving feature updates. I wouldn't recommend learning how to use it for this purpose, but it is one of the few options I've found.
OpenStreetMap has a speed limit value for
most routes where you can view different speeds as different colors, so I use that to review a route and confirm it's
https://www.openstreetbrowser.org/#...54&basemap=osm-mapnik&categories=car_maxspeed
View attachment 8526
I set my GPS to "avoid highways," preview the route, and then go. If I end up on too fast of a road I'll pull off and reevalate my options. I do wish there were a better solution of a good mapping and navigation software where you can just set a maximum speed and have it attempt to plot a route based on that.
ScootRoute having ads so that was an immediate non-starter for me.