For some reason, my 1x1 rib looks worse when I knit in the round than when I knit flat. My knit stitches are very wide and almost look like ladders (see the swatch below)
That is curious. You’ve tried all the things that come to mind to tighten up ribbing. Does it occur with different types of yarn: wool, acrylic, cotton?
This isn’t a solution, more of a work-around. You could twist the knit sts either every other round or every round. Unlike the twisted rib videos, you only knit into the back of the knit stitch, not into both knit and purl sts. I’ve used it for its decorative appearance too.
I am sorry for that I do not have good fix but I know why it looks worse for you when knitting in the rounds compared to knitting flat. When knitting in the rounds you always purl a whole column and always knit a whole column. Thus if there is a difference in tension between knit and purl it will show for the whole column. When knitting flat you will both knit and purl the same column so it is sort of fixing the problem with different tension.
I bet the problem will disappear after a few washes when the yarn has had a chance to move between knit and purl columns. If you truly want to fix it without washing the only thing you can do is trying to achieve more even tension for both knit and purl.
Ribbing is not all equal. Some are not as tight as others. 1x1 rib is rather loose… you may find you will get better results with a 2x2 or even a 3x1. Try a variety of different combinations to find one that will work for you.
Why does it work this way? Every time you move from front to back, and in reverse, there is a bit of slack in the yarn. So you are making a lot of changes back and forth, so have a lot of loose yarn there! When you do fewer changes, you get a tighter rib.
The alternative is to do as Staci (VeryPink) shows you… to tighten up the yarn when switching frin knit to purl. https://verypink.com/2017/04/26/tips-nice-ribbed-cuff/ (at about 6 min) Extra step, but worth it.
I learned to rib by using a size smaller needle, even hook, than the body of the project. Does a good job, actually…