I hear ya. My 3D printing experience is only with FDM, no SLS yet. I'm thinking about getting one of the really cheap new liquid resin printers though, to broaden my horizons. I think the liquid resin prints would be too fragile for functional parts like this, but it would be useful for figurines and other decorative stuff. I've printed some nylon on my printer before, and I'd 100% agree that it would be a better choice for parts like these mounts than PLA is.

I'm all good for mounts on my bike right now, but I've been thinking about trying to whip up a design for a better mount for my Niteryder light and Garmin. With my saddlebag under my seat I'm limited on mounting stuff to the seatpost, but my Brooks saddle has loops for hanging stuff from the back of the seat that I might tap into.

Rotating the print as you suggested would definitely lessen the fragility due to layer delamination across the thin cross sections of those mount flanges, but also would come with its own annoyances, like requiring support for them, since the flanges would start above the print bed. I think with a more durable filament that delaminates less like PETG or Nylon and some generous fillets the current print orientation would be fine.

I'd never use PLA for anything designed to hold parts onto a bike. I consider it way too fragile for something like that. I use PLA for figurines and decorative stuff like that, but any functional part I print I use PETG on. I've printed some stuff in ASA, which is designed to be UV-resistant for use on stuff that'll be outdoors.