If I continue to run into the same paywall, I would consider buying into it. If I bought content, I would want it to show up in search. I wouldnt know I want to buy it, if I dont run into it first.
Then Google should work on a way to connect your purchase with their system or give you ability to inform them you’ve purchased a subscription so that only you get to see search results from that paywalled website, and not others.