What parts of Heroku in particular are you interested in seeing in an alternative? If a friendly user interface is a big part of the ask, your options are unfortunately limited (at least among the big cloud providers, I'm unfamiliar with smaller providers).
AWS's Elastic Beanstalk doesn't have any UX to speak of (just a few options to fiddle and some weak logging support). It's a very raw service, much like the rest of AWS (rock-solid infrastructure to bring-your-own stuff). They take care of infrastructure but developer pleasantries are entirely up to you.
App Engine is significantly better on the UX front - you get error reporting, metrics, logging, etc all in a single cohesive web app. In my experience I hit some hard to debug / resolve quirks, but that is very much a ymmv situation. It can be tricky to figure out how to configure the right pieces / permissions in their new app engine variant (docker-based). I wouldn't use the classic variant at this point, it's pretty heavy on the vendor lock-in front. It's great if you need the specific capability of classic app engine but that's most likely not what you need.
If you're using Heroku's hosted postgres, know that GCloud's postgres support is still "beta". AWS RDS on the other hand has very good postgres support.
In both cases, deploys aren't just a git push, but use a custom CLI (`eb deploy` and `gcloud something something`). They're also both pretty typically tough to get to the first successful deploy with - for example Elastic Beanstalk will spend quite a while attempting to recover from deployment errors, and if you've never deployed a successful version it's very bad at that, and it also blocks deployments while it attempts to recover. So you end up stuck while it attempts to recover from a problem it will never recover from for a bit (this has been a problem for literally every beanstalk service I've ever deployed, heh).
You can also go something like the hosted Kubernetes route. Currently GCloud is king here, but naturally that's a command-line only UX unless you deploy your own kubernetes UI service (unfamiliar with options there)
AWS's Elastic Beanstalk doesn't have any UX to speak of (just a few options to fiddle and some weak logging support). It's a very raw service, much like the rest of AWS (rock-solid infrastructure to bring-your-own stuff). They take care of infrastructure but developer pleasantries are entirely up to you.
App Engine is significantly better on the UX front - you get error reporting, metrics, logging, etc all in a single cohesive web app. In my experience I hit some hard to debug / resolve quirks, but that is very much a ymmv situation. It can be tricky to figure out how to configure the right pieces / permissions in their new app engine variant (docker-based). I wouldn't use the classic variant at this point, it's pretty heavy on the vendor lock-in front. It's great if you need the specific capability of classic app engine but that's most likely not what you need.
If you're using Heroku's hosted postgres, know that GCloud's postgres support is still "beta". AWS RDS on the other hand has very good postgres support.
In both cases, deploys aren't just a git push, but use a custom CLI (`eb deploy` and `gcloud something something`). They're also both pretty typically tough to get to the first successful deploy with - for example Elastic Beanstalk will spend quite a while attempting to recover from deployment errors, and if you've never deployed a successful version it's very bad at that, and it also blocks deployments while it attempts to recover. So you end up stuck while it attempts to recover from a problem it will never recover from for a bit (this has been a problem for literally every beanstalk service I've ever deployed, heh).
You can also go something like the hosted Kubernetes route. Currently GCloud is king here, but naturally that's a command-line only UX unless you deploy your own kubernetes UI service (unfamiliar with options there)
Unfamiliar with Azure's offerings.