I find it infuriating that navigation apps throw ads when I'm stopped at a red light. This is THE moment where I should glance away from the road and plan my routing
If you're in the unenviable position of being unable to edit your phone's hosts file, you can block most ads using a DNS-over-HTTPS provider. Mullvad has a free service.
https://mullvad.net/en/help/dns-over-https-and-dns-over-tls