Commiserations form a fellow skinny runt I have exactly the same problem.

Steer clear of stretch denim as it gets too soft with body heat and ends up slipping off. The heavy rigid denims are best. Santa got me some really cool Lee ones. A bit exxy but worth it They are a boot cut style. Low rise but not too low. Sorry I can't remember the style but will sus it out later as they are in the washing machine as I type this.
I tried on a few different cuts with Lee and it;s amazing how the sizes differ with the same brand. Very frustrating!

With the ones you already have, would it be worth your while taking them to get them altered? You may just need a dart in the waistband...