Prebid ID vs GAM Secure Signals

​As a European publisher we are currently have zero 3rd-party IDs running and are looking to build an identity strategy from scratch. In prebid we run adform, pubatic, Ix and Criteo. We use GAM as our adserver, with a mix of CTB and Display

We are struggling on implementing an ID-strategy without devaluating our own 1p data.

We understand we are missing out on revenue and want to implement some ID solutions without fully compromising our users data, but are hesitant on how to do this. Criteo and id5 seems to be an obvious choice but is it worthwhile without hashed ennails?

All advice is welcome

Which prebid Id modules do you use? Which secure signals do you have active?