T-shirts and leggings advice please!

I've searched, but many of the results I've found so far are over a year old, so I thought I'd "refresh" the topic here; I hope that's okay.

I'm 5' 2.5" (don't leave off that half inch please!), and I've recently gone from a 14/16 to a 4/6, XL to S in tops, and I'm really struggling with finding clothes, but in the opposite way! I'm looking for a lot of stuff, as my entire wardrobe needs a redo and I live in a clothing desert, but for now I'll keep it to 2 things: leggings and t-shirts. I've ordered and returned multiples of each, including Old Navy and Amazon, and I'm so frustrated.

For shirts: I'm high-waisted, so some crop tops fit exactly as I want: right at the waist so they work with (for example) a flowy skirt. I found some at Old Navy that would have been perfect if the neck didn't make me feel claustrophobic, so now I'm searching for v-necks or lower scoops. I'd like them snug but not super tight, and definitely not a boxy fit.

For leggings - again, high-waisted, don't sag/fall down, and on the thicker side for durability. And in colors - why is everything I'm finding so drab??

I would be so grateful for any and all suggestions, thank you!!!