Your signature updates after every activity and will rise and fall due to Training Load alone.
Breakthrough events (BTs) confirm a bump in signature values but are not necessary for your signature to align.
A Near BT indicates your signature is dialed in (assuming the activity included true max efforts).
Some users can go for months without BTs while others will challenge themselves frequently especially if they compete or enjoy pushing themselves on hard group rides or ZRL.
This is where MPA and TTE fields or the new Xert Dashboard can be referenced on a Garmin to let you know when you are close to a BT.
If you want to confirm your numbers are in the right ballpark, I suggest you try a “fitness test” workout in Slope mode (if indoors). Try to exceed target watts and duration on any intervals designed to drive you to a failure point. Even if you don’t achieve a BT you’ll have a good idea how aligned your signature is and whether any manual adjustment is warranted.
PP is the least sensitive value in terms of variability and the effect on your training.
It’s not uncommon for users to generate 100-200 more watts during sprint efforts outdoors compared to indoors on a trainer.
Also, PP is literally your 1 sec power. Many cyclists can attain that after spending hours in the saddle. Not necessarily sustain it, but come very close to their max power. You just can’t hold it for very long like pros can.
You may have noticed most sprint intervals change to Slope mode when running EBC indoors.
The goal is a max effort rather than a specific watt target.
MPA is only drawn down when you exceed TP and should return to normal during recovery although your ability to draw down repeatedly declines over time due to fatigue.
Xert 2.0 (under development) will model that fatigue and how it affects MPA and TP during rides.
Lots of newbie tips posted here if you haven’t see this already –
Onboarding steps for Xert trial users and newbies - General - Xert Community Forum (xertonline.com)
Welcome aboard. 