Azure Compute Decision Tree is a simplified decision making assistant that lets you decide which compute resources to choose based on your compute requirements. It is a comprehensive decision tree considering the lift and shifts and new developments. But developing new applications are much simpler given most services support multiple runtimes as well as containerisation.
Ideal for event-driven short live processes such as HTTP requests, multiple service triggers or simpler schedulers. Gives you ability to host as managed code as well as containers. So if you are thinking of long term expansions, containers is an option to consider.
Functions is a famous option when you pay for number of executions which is available with Standard pricing. But if you need to extend networking you have to select another pricing level.