How to keep squid soft and fluffy?
The recipe in the video appears to cook the squid entirely, then mix it into the rest of the dish, then continue to cook the entire dish. (I suspect the recipe's creator has different expectations regarding the final texture of cooked squid)

Overcooked squid will be tough or rubbery whenever over cooked, whether too hot, too long, or both (which will happen in a pressure cooker, unless cooked so long that it breaks down.)

Sous vide is ideal for precisely cooking proteins, squid included. Most recipes call for around 60c for 1-2 hours.

Pan frying is also effective, as it gives much more visibility and chance to stop cooking at the right time. Many squid recipes call for 2-3 minutes saute.

In any case, cook the squid to preferred doneness in parallel to preparing the masala, then remove both from heat and combine. The intention should be to stop applying additional heat to the squid once it is cooked.