We’re seeing more rule changes for allowed equip in the last handful of years than the last couple decades before it.
Last season was:
optics under 4.5x
Triggers over 4.5#
No adjustable gas blocks
Pic rails at least half length of rail at 3, 6, 9, and 12
Nothing over 20”
The only thing I can say, whatever you build today won’t likely be at the forefront of the rules in a season or two, and the NRA HP and CMP rules are just disparate enough to ALMOST make two rifles necessary if you’re going to swap between the two. For most folks, both aren’t available locally, so jumping into the one nearest you, and building a suitable rifle makes the most sense.