The Garmin bands keep improving (becoming more flexible) with each generation. My first came with a F5+ and even those bundled with the F6 we’re a nice improvement.I was a bit surprised by how flexible the standard Epix band was
I generally avoid using third-party bands with expensive watches but the two Abanen ones I have feel very secure. I generally only use them for running and occasionally sleeping (much like I do with Apple‘s sport loop).