I got sheets from Costco too... best sheets I’ve ever had!

I bought two sets of Pratesi sheets about 8 years ago. They are Italian-made, Egyptian cotton and wash/iron like a dream. I purchased them at Home Sense (aka Home Goods) so they weren’t as expensive as you would think, especially if the cost is averaged over the time period.

I’ve been happy with ours from authenticity 50. Seed to stitch made in the USA: https://authenticity50.com

Historically, I like Ralph Lauren sheets. Now I am using Frette, but it's only been a few years, so I can't speak to longevity.

Love shabby chic sheets from Target. They are surprisingly great. Try them. Very little to lose money wise,

I have just recently been googling this very topic. I was surprised to read that LL Bean sells very good quality cotton sheets. I didn’t even know that they sold sheets. The other thing I learned is that you should not get caught up in going for the highest thread count. After a certain number ( I think they said 300) it isn’t a major factor. Sleeping on heavy cotton sheets is one of life’s little joys IMO.