FWIW Garmin is NOT requiring logos anywhere, according to DC Rainmaker. They just want a text attribution, similar to the tiny and unobtrusive OpenStreetMap (or whatever company) text at the bottom of literally all maps on the internet.
I don’t think this is an effort at free advertising by Garmin (as Strava suggests) but rather a reaction to Strava’s aggressive API changes and claims of ownership over all data provided to them.
I also cancelled my auto renew on Strava; none of the paid features are worth anything to me and the company seems to be run by unbelievable a-holes. I’d rather spend my money elsewhere.