Wifi hot spot vs gps or both?

↑ What they said.

If you either don't wish or are unable to have local cellular network coverage, you can still use the smartphone from your home country for car navigation. First download the appropriate maps for Google Maps over WiFi; even if your phone does not have a local cellular connection, the GPS in the phone will then function fine with Google Maps for driving directions and navigation. The one thing you will lose is realtime information on traffic conditions. I did this with a different application in Croatia in 2017, but since then have been using Google Maps in other countries without issues.

Those GPS you rent from a rental car agency are utterly useless compared to the aformentioned pre-loaded google maps

Thanks all.
@GeoffB
you’re right, I don’t wish to swap out my SIM card. I’ve read it changes your phone # while there, and i need to keep mine intact for various reasons.
No one here has addressed my question about having the wifi hot spot for the car. Wouldn’t that allow me to use my phone pretty much all the time for real time Google maps?

Hi. You could get service with your existing SIM if your cellular service provider has an int'l (data) service plan. (My previous comment was not meant to imply that you would have to change your SIM card to get local service; that would be just one option.) For example, most T-Mobile plans include SMS and LOW-speed data service while in most (or all) European countries, and one can add HI-speed data for an additional daily or monthly fee.

I have no experience with using Wi-Fi hotspots. It is an option I have explored and rejected before past travels to Europe; I found that downloading the maps worked fine for my needs -- and on very rare occasions I paid for one day of int'l service from my provider.

I don’t wish to swap out my SIM card. I’ve read it changes your phone number while there, and i need to keep mine intact for various reasons.

Respectfully, before going down the "in-car wifi hotspot" road, I would urge you to carefully examine your premise, think about your actual, specific needs, and investigate alternatives that would address those.

You may well have a valid reason to want to keep your phone connected to your home phone number, but the in-car-wifi option will be expensive, awkward, and has plenty of downsides: slow, limited connectivity, one more thing to keep charged, one more thing to lose, break or get stolen, one more gizmo to carry around (you're not going to leave it in the car when it's parked, are you? etc. etc.). Maybe for you, the in-car wifi is the best solution, but for most people, it's not a wise choice. Getting a local SIM is cheap, easy, reliable, and there are lots of reasons that's what almost everyone does.

If you've already really examined what your specific needs are and investigated the alternatives, ignore the above. But the way you phrased your question (first you add a car-based wifi-hotspot, now you're looking at adding a GPS, too...) that hints that maybe you have not looked carefully at all options. Apologies if I've assumed incorrectly. Good luck.