If the excess really bothers you, there are also these little straps you can buy with little suspender clips on either end, and you can use them across the corners to snug up your sheets. I had some knit jersey sheets once that would not stay on until I got some of those.

Edit: These thingies, sheet stays

specific corners

You just go clockwise.

They were store brand at target. I'm also broke as shit, but also have really severe sleep issues so managing anything that interacts with sleep is super important for me and I'm willing to spend a bit more on it

If I don't wash bedding often enough my allergies trigger a chronic ear infection that makes my sleep worse. So it being painless to wash bedding and put my bed back together is a very helpful

(which is why I have two of most things that go on my bed, so I can wash some things before I even take my bed apart and its easier to get it all put back together before bedtime)

My armspan is just below a king sheet's short length, so I always just check which side causes more shoulder strain/is more loose at full stretch.

Also yeah, always get a size up if you can/value your sanity.

I make mine fit even if it folds my bed in half

POV: my linen closet

I'm sorry, but do you sleep on a King size bed, or a California King size bed?