Sat Navs are for cars, well it's built in isn't it.
On my bike it's memory combined with some well highlighted notes on the tank bag, then a real OS map in the tank bag for a look up where to explore when I get to the area I intended.... Or when I make a monumental screw up, stop and use my phone maps!!!!
Front door every time (although it is on the side) back door are bi folds 4m wide so too cold this time of year! (Not sure that was the answer you wanted Nick😅)
This is where "you get what you pay for" meets "the law of diminishing returns". I've gone for the middle ground and got one that fits me comfortably, has the right safety rating but was still in my budget. To answer your question, if you go down and it saves your life, what is that worth?