Generally speaking if it's the platform you have you will shoehorn the shape of your code into a serverless shape bucket even if it has no business looking like that. These architectural shortcomings will inevitably come back to haunt you.
Also most of these platforms amount to cgi-bin v2, meaning things like memory leaks and requests that hang get swept under the rug. Meaning you already have very difficult to diagnose failures and when you do eventually go to migrate you will find your code is full of these smells making it harder to reform into something reasonable.
That is also putting aside the spaghetti nature of intertwined functions of any serverless codebase of scale, the huge IaC overhead if you go with something like AWS Lambda and the massive amount of incidental complexity that serverless advocates try to make you look the other way for (hello API Gateway).
