It all depends on your use case. You mentioning "scheduled task" appears you want to use a Worker Service

If you want to trigger your actions you can host a webapi, too.

Bottomline: Both use cases suffice your needs so your course depends on where you want to "control" your app ( set delay, maybe sometimes start the action manually ). WorkerService -> Config file on the host Api -> Configure from client

What you mean integrate on "all my APIs are in Azure App service and this has to integrate with Windows desktop application.". Try to explain a little bit what's your requirements.

If you want to Read/Write a SQL DB on premises, you can use a Azure Gateway without deploy anything in your server, another choice with SQL Server is to move the DB to Azure (if supported). You can use the triggers on Azure Functions to write/read something on Azure Storage, from your Server you can read the storage and perform some tasks. As you can see there are multiple choice without writing much code on premises, try to clarify your requirements.

If you want to be a Web developer with knowledge in another frontend and NoSql technology, maybe continue with Flask. However, if you want to create very fast solutions to grow up with a new business and merge these with data analysis and other tools, Django is the answer. Basically read more about the service architecture where you feel more comfortable, Microservice or Monolithic, but please will not married with any because they solve issues to different contexts.

Bottle is much less bloated and fast. Its built-in templating system is one of the fastest as it compiles the templates in bytecode. Also Bottle has no depenencies, preventing dependency bloat.

For starters flask provides a beautiful and easy way to create REST APIs. Also its supported by excellent beginner docs as well as a very active community. Another good thing with Flask is its widely available list of plugins which allow you to build as you go. Its also good in performance and can scale to a quite decent level. However, if you are sure your project is going to be fairly big, it would be better to start with Django as it provides a lot of features out of the box and is extremely stable in performance. Both these frameworks have support for Swagger, JWT, Coverage Report although you have to install plugins for them. Deploying both of these are fairly simple and there is huge documentation available. Django has one of the best documentations I have come across. I hope I was able to answer your queries.