As has been mentioned already there is no "perfect" spectrum (other than the sun lol 2000 PPFD, true full spectrum and free), more so pooling resources and experiences to try and decide on an overall favorable spectrum for indoor growing with what is currently available.
In reference to the N and P fertilization relation to b-myrcene decline. I did a bunch of reading into building an organic soil and spoon feeding soluble fertilizers intermittently to maximize growth and retain the benefits from organic living soil. Ammonium and soluble/available forms or phosphorus fertilizers eradicate the micro life which could hurt cannabinoid/terpene production.
This link is to a post I put together on plant nutrition with info I found useful from jidoka and Harley Smith, it mentions the P and micro life interaction briefly (at the bottom is a link to my post on ammonium/phosphorus interaction with soil microbiology):
https://www.icmag.com/ic/showpost.php?p=8495077&postcount=5585
I had a good conversation with Tycho Monolith awhile ago also about whether a landrace strains cannabinoid/terpene profile could change over ~20 years of being grown/bred indoors away from its home environment/pests/normal stresses. Indoors ~10 weeks can mimic a full outdoor season, seems to me it could cause rapid environmental adaptation in bred offspring to the indoor environment as defensive traits are not being used and probably lost (unless original parents can be maintained).
I didn't mean to specifically target any one metabolite or even spectrum studies or the resulting benefit but rather point out expression based on maximums does not ensure maximum "natural" expression but rather pushes cultivar expression into a envelope of environmental cues that limits diversity in expression and maximizes those metabolites the plants all share in common (thus making for alot of pot that seems alike)
not so much in my garden