I am new to running (sounds like I am even newer than you!) but I come from a cycling background. I have completed 8 weeks of transition and one Base block and am in my Base 1 recovery week beginning today.
In my experience as an elite athlete, you have to build a base before you can add intensity. If you follow the strength and sprint intervals, you’ll be building the muscle memory you’ll need for the speed down the road while incrementally building speed in general. Also don’t forget that you can do pick-ups and some speed work downhill sparingly in the base block which will help. Mostly base building is the foundation. It’s not pretty. It’s laying concrete and rebar. The house can’t be built without a foundation!
How long is your training plan for your objective? Once you get past your base building you should feel faster in your Z1 and Z2. But I would give it time.
It seems counterintuitive, but that’s why the guys wrote a book about it.