The whole point is that there is no moral/ethical way to enter a “contract” with a party who has been knowingly siphoning (read “stealing”) your and everyone else’s data without being upfront about it since time immemorial. Oh you want to enter a contract with me? Send me an invoice at the end of every month about what data you collected from me and how you used it to pay for the services. Otherwise, there’s no way they won’t be double dipping.

Or they can drop the adtech business or spin it out as a separate company. But either way currently there is no way to fairly deal with ad tech companies with thinly veneered “free” services on top.