Hi Sydney - Both images are lovely portraits of characterful leaves. You did a good job darkening the backgrounds - both images look natural.
As far as increasing contrast without increasing exposure, my go-to method is to dodge and burn. Not sure if you have any plug-ins for selecting luminosity ranges, but the built-in dodge/burn tool in PS does a reasonably good job.
On the thin-leaved image, you could try dodging just the lights:
On the bigger leaves image, you’d need a couple different “zones”. I dodged both the lights and midtones, to bring out more of the bottom-most leaves that were in focus. I also burned the lights on that uppermost leaf that is really bright because it is OOF and the brightest bit in the frame. OOF elements aren’t a deal killer, IMO, but generally they shouldn’t be the most prominent element.
As far as getting more of what you want in focus, while leaving the background OOF, you could try focus blending. That is not my strong suit, so take my advice with a grain of salt - try focus stacking just the leaves and then either take a shot with the background really OOF or use one of the leaf shots that has a soft background. If you want more ideas on focus stacking, this post might help: