Depends - in the pure technical "implementation" level, only limits I've found are the ones with outdated knowledge - libraries, platforms, availability of some things.

But one big limit is the DX. Their choice of DX is usually abysmal - ironically, just like an average devs. They seem to lack the aesthetic instinct for code, so you have to really point them hard into the direction or provide a sample of the expected DX, for them to still fight against it at every turn.

While understandable in a way, as they are trained on average code and most code will now be written by the machines anyways making the DX "less relevant", it's also a giant code smell, as bad DX tends to point towards bad internals and wrong decisions along the way.

So not really a technical limit - they swallow anything you throw at them, even the most complex cases - but more of an aesthetic limit in terms of taste.