I want to make a simple stepper-like form in Microsoft Teams, and I already have and angular application containing this form (that I want to display in Teams). The thing is that in vscode there is only a template for React, and no template for Angular. The question is, is it mandatory to use their templates in order to make the tab thing in Teams ? Does anybody have a github repository example with an app built from scratch without templates ? Or should I stick with the template, and translate everything from my angular component to react ?
You do not need to shift to React from Angular.
Teams toolkit defines the whole lifecycle of teams app development very clearly in teamsapp.yaml and teamsapp.local.yaml.
You can either add these files to your existing project to make it be recognized by Teams toolkit, or replace the source code in Teams Toolkit React template with your Angular code and update the yaml file to make it work well with Teams toolkit.
You can go through this wiki to understand how Teams toolkit tackle teamsapp.yaml. Teams Toolkit Visual Studio Code v5 Guide