>Not sure why, but single knots always come undone for me pretty quickly

Since you've read about knots I'm sure you know this, but it's worth mentioning for others in the same situation - if you find your laces come undone very easily with a simple traditional knot it may be that you're not balancing the starting knot and the finishing bow, leading to a "granny knot" - https://www.fieggen.com/shoelace/grannyknot.htm