☒ if you've not deployed the application yet then you can roll back the database migrations first and then make the changes. If you have already deployed the application then things get a bit trickier because you've already gotten data populated on those columns. If you've already deployed the application or have team mates and the code has already been merged then I would create another migration.

I could have a look this week. I'm not sure if there could be something that's changed with the Rails version or of there is some other hiccup that could be going on.

 ☒ I didn't see a link to the code base. Did you share it. 

 ☒ I haven't messed around with those options to know if they are making any difference or not. You could always make a custom upload controller, use the new url instead of "this.url" which is taken from the direct upload, and return a variant record. However, you'd still have the full size image stored via ActiveStorage and may need to clean those up periodically.

 ☒ I haven't looked much into this, but with AL2, my guess would be to use the Procfile to declare the service to run. I would probably also look at running the Worker environment type instead of a Web worker. The rest of the config should be pretty similar