There was already a plan by salesforce to kill it and make it into salesforce functions. Someone else here called it project periwinkle.

That's frustrating. Heroku is one of the nicest cloud services I've ever used, and am currently using.

Salesforce has been holding heroku further and further out over a ledge they're definitely not planning on supporting it for much longer.

Edit: I only had one project left on heroku and I migrated it to Render a few months ago.