Regarding grains, I think that Rahr 2-row is the best among the mass produced and available to virtually anybody in the USA IMHO. However, if you are wanting to try different grains, over the past ~6 months, I have become a huge fan of Epiphany Malt (North Carolina). To my knowledge you can only purchase it through Atlantic Brew Supply out of raleigh. For me being in NC, this is no big deal and I've ordered online and gone there to get a sack of their foundation 2-row malt in person (1.5hrs drive for me) when I was in Raleigh for a different reason. If you really want to geek out on malts, I would encourage you to visit their website which includes a ton of cool stuff including their efforts to move towards improving their carbon blueprint. The founder, Sebastian Wolfrum, is from Germany. He worked at Ayinger and later became a certified brewer and maltster in Munich before coming to NC. When reading through Epiphany's website, it becomes clear that they are focused on producing very flavorful malts, even the "generic" 2 row variety. They are all a bit darker due to extended kilning if I were to summarize their approach. I've brewed with their foundation 2-row as well as their munich malt and I've tried (eaten) these along with their pilsner. All of them are VERY flavorful and true to their style.
Warning tangent! Recently I brewed an altbier, and during planning I did a taste test of weyermann's munich type I malt (which I really like) with Epiphany's Munich malt. It was a slam dunk! Although I really couldn't do a blind comparison because they looked so different when I tasted both, Epiphany's was brighter, breadier, and had a better malty sweetness than weyermann's. It really wasn't even close. do think some of this might be due to the fact that I got the weyermann's through more beer and epiphany's just seemed MUCH MUCH fresher as well. the kernels were much more consistent, and not as "dry" looking and broken up as the weyermann's munich Type I from more beer.
So I would encourage you if you are in the mood and have the motivation to improve all of your aspects of your NEIPAs, even if its the "lowly" two row malts, I've become a big fan of Epiphany and since I've started tasting the grains more and more when determining grain composition for any beer, I do believe that this "might" even make a difference in a highly hopped beer such as an NEIPA.
Cheers!
EDIT: I have not had Mecca Grade malts for comparison. I do hope that the buyer of Mecca Grade is as passionate about malts as the founder though. Only heard great things about Mecca Grade.
https://www.epiphanymalt.com/
https://www.atlanticbrewsupply.com/