It looks like EON, who make one of the inpressive Gamecube HDMI out adapters, have made one for the N64.
It's available for preorder from Castlemania games.
https://castlemaniagames.com/collections/frontpage/products/eon-super-64Per the site, "The Super 64 delivers a clean 480p zero lag image over HDMI without the need for external power. Additionally the Super 64 features a new “Slick Mode” button that when activated buffs out hard pixelated edges, giving an all-new look to our favorite N64 games."
$150 is definitely pricey. But the Gamecube variant was the same price and most consider that well worth it. You can also probably find youtubers promoting this and get 10-15% off using their promo code.
Hopefully this works well. And maybe someday Insurrection, or somebody will make a more cost effective variant. Until then, at least there's this.
Personally I am still on the fence and will probably wait until the next batch, as I almost never play N64, and they will work out the bugs and probably deliver a better MK-II version next year. But it IS enticing.