Earlier quoted context omitted.
They have not pushed out any notable updates in a long time, bugs have remained unfixed for many years, customer support is unhelpful. All of the most talented engineers at Heroku left, the team now functions as an internal infra team for Salesforce. It's a zombie of a company. The product and pricing are pretty good for small projects, but almost everyone outgrows Heroku well before they transition from "small" to "…
> the team now functions as an internal infra team for Salesforce This is definitely false. Though some internal apps are deployed on Heroku, it is not the primary deployment target for new projects. Heroku staff work on Heroku. Salesforce has a large internal infra program and team that has no overlap with Heroku. past codename projects have been proposed to change this, but none have ever come to be.
You understood it as running sfdc code on Heroku which is not happening—but was proposed as part of Shinrai (a failed project). What has happened is many if not most Heroku employees have moved away from working on Heroku and are now working on Salesforce Functions aka Evergreen.