Want to port to T-mobile after phone's lock-in period ends

My google pixel came with a locked in Mint subscription of 12months. that ends in 2 days and I want to port to T-mobile. but the problem is, i need an ACTIVE plan to port to T-mobile. So if I wait for my subscription to end, I won't have an active plan anymore.

But I am worried if i port my number to T-mobile before my Mint subscription ends, I don't want to violate the lock-in period.

Would really appreciate any suggestions