Unlike a car the body has 3 types of fueling: LO7 of Unit 1 - Energy systems and their relation to exercise (2021) - PT Institute - for your endurance/touring question you are most interested in your aerobic power, and as mentioned above is also dependent on adequate refuelling.
In some ways you are already covered by things like the FTP calculations as that covers your aerobic power too. Also your TTE and VO2Max.
In theory, the distance you could cover could be reverse engineered by figuring out the elevation provided, and the power required/desired, which can then be compared to your FTP to produce a Load figure. But then all you’ve done is provided a rather complicated way of replicating your Fitness figure, as there’s some evidence to suggest that your chronic training load is a good predictor: Volume vs Intensity | Alan Couzens
There’s another person here who is using Machine Learning to estimate: I would like to get your opinions on the FTP model I developed (now see ::::: Riduck.com :::::)