I’ve heard good things about Uniqlo heat tech layers too but I bought these at Costco (pants and shirts—they’re on sale right now to be even cheaper) and they save me every winter!
They’re so lightweight you can put them under anything without looking bulky and if it’s really cold I’ll double them up (if it’s in the negatives or I’m going out into a snowstorm I put on fleece tights underneath that)!
Busted the pants out for the season when I walked my dog this morning because it was about 45 degrees and I wanted to wear lightweight pants… they run weirdly small though so BEWARE