for each process anyways you would open a new project and each project is connected to its own repo..so that any process you want open studio connect repo and as the local git files are stored from next time when you open process corresponding repo would be connected
whenever new repo is there we are maintaining the yml and pipeline files in code itself so we create our own framework in which they are included only thign they need to change is the variable values at top of file for folders they need to be deployed in dev and prod…and yea to schedule a trigger we need to do one time setup whenever a new repo or process is created..but remaining pipeline level details would be picked up automatically as the files wqould not change and we use relative paths in them
if you want to automate go with using power automate to create new repo and rule for process based on details you provide..the same can be tried is UiPath integrations service azure activities
cheers