I primarily use Google, Waze and sometimes Apple (in work vehicle) for navigation.
I have never used a factory setup that is as user friendly as any of these.
It's worth mentioning that they are all much easier to use with CarPlay or Android Auto.
I have also rarely had a coverage issue due to poor cell service either.
It's too easy these days to have free navigation.
I would buy an inexpensive Garmin or TomTom before a factory system if concerned about cell coverage.
Toyota is going with MapBox for some 2023 models. The video I saw about it was impressive. But you are right there are cheaper alternatives to the paid subscription. I had Garmis in the past, and liked them. The only drawback was you had to hide it when you parked.
I think it's very clear that it's all included for one price, don't think you can pick and choose what you want under the Drive Connect Heading, which gives you a one year "free" trial on 12.3-in. Toyota Highlander Audio Multimedia with JBL®12 Premium Audio Platinum, Limited, Platinum Hybrid, Limited Hybrid XSE .