Altium designer routing problem
The way this is typically done is with micro vias (via less than 6 mil in diameter), this will also add manufacturing cost. Compare the manufacturing cost to the cost of the package (if there are different options go with a different package).

You'll need to add another via size in the via template and change the DRC rules if you use them.



Source: https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/649693