I've been a paying member of heroku for nearly a decade, and pay them $1000s of my personal income monthly. I think their product has been brilliant. I just defended them yesterday in a HN comment.
I do, however, use their free tier to test things daily. This news puts me in a bind. It's work that I hadn't planned, and I only have 3 months to find a solution for it when I have my own roadmap already planned.
This is me as well, I pay for production but the testing stage of the heroku pipeline is free dyno. I gotta move both to someone else or pay for the testing env on heroku. I'm not a swe, so it will be a bit challenging for me to migrate