Tangential: Does anybody know or have a reference about whether the opt-out-or-can't-even-opt-out tracking in Android, Windows 10 and possibly iOS are GDPR compliant? My reading is that it isn't, but I'm not well versed on the subject.
I should mention, that demanding tracking may well be okay in GDPR, in necessary contexts: for instance a banking service may have to do some natures of fraud prevention using tracking, perhaps of recent internet facing IP addresses used and may have a regulatory need to do something like this.
Also bear in mind that GDPR isn't the only law here. If you want to access data stored on a user's terminal (mobile device, laptop, etc), then you likely need consent too under ePrivacy: for example "Article 5" https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX...
Using any map application (especially google maps) does not actually need to store my location for posterity to give me useful service, and I did not opt-in but android still does; Perhaps it's because I haven't been back inside Europe in the last month or so (and when I do, I'll get a "please opt in" prompt).