Every little bit helps.

Unless you can get a 91/135 job flying a turboprop on your days off, CFI is probably the best way for AD personnel to build time since is schedule is flexible and the customer is usually more flexible as well.

Getting over the 2K hump is good.

Checking more boxes on the app is good.

Actually working as a CFI is also good, particularly if you don't have mil instructor time.

But do your homework with regards to the DPE you use, failing a checkride would probably do more harm than 300 hours is worth.