[IncRnd]

Have crypto agility, so that when you want to transition algorithms, the move will be as seamless as possible. You can start to use a blended or hybrid crypto today, where you simultaneously use both classical and pqc algorithms. For your classical algorithms, you should adjust your keys' security strength in accordance with your threat model. See CNSA 2.0 for a starter reference. For data in motion, you can use two VPNs, configured appropriately.

There are a number of things you can do today, more than I listed. I suggest you discuss with an appsec person who is familiar with your threat model.