first things first: Welcome to the Systm forum!
Do you use your Bolt/Roam already or do you plan to buy one and would love to see the functionality you describe?
I am a proud owner/user of a Bolt (series I) and love it!
My navigation settings are that my navigation „arrow“ is always heading towards riding direction and the scale is in the 200 m range (sorry, metric units).
Here comes the verdict: I have a 99% hit rate in following the route I have chosen. For me it performs (kind of) flawless and I use navigation every time I‘m in holiday on unknown territory.
Yes I have the arrows settings the same and scale similar, I do find that I often have to zoom in and out to see the level of detail that is relevant to my speed though. Not a huge problem, but a setting for it to adjust automatically would be helpful.
Not really a solution to your query, but it may help a little: I’ve recently removed the speed indicator from the map-screen. It makes the actual map just a tiny bit bigger and helps with the overview.
Added benefit is that I’m less obsessed about current speed and just enjoy the ride.