Nothing wrong with cloud services, but like any external dependency you need to look closely to see who it is you're dependent on, and what the risks are. Garmin is a cloud service also - the maps you download are in S3 or GCS or similar, the traffic updates are licensed from yet another party by Garmin - and delivered using cloud provisioned services. If Garmin goes so do these services. Cloud or not doesn't matter, it can be AWS, GCP or a private data center (and in-house cloud provisioning). Garmin though would do an orderly shutdown, give you advance notice, perhaps discounts on replacements, or if they're acquired the acquirer will. They're in it for the long term and want customers to buy an assortment of Garmin products, and be in it for future product generations as well. The customers as much as their products is what makes them valuable and a good investment.
You just need to be a little more selective. Or accept this might just go away one day. Really small startups though in this situation will often open source the bare essentials, as a sort of guarantee against exactly this. (Which you can then go spin up yourself on AWS or wherever.)