Looking into 6970: Out of focus and exposure issues as seen on the histogram.
You have missing whites and also part of the highlights are missing.
Furthermore, the picture shows disturbing elements that should either go, or be in focus, like the bee
and the second flower.
Idem for 6945: out of focus and exposure problem.
6992: out of focus. The exposure is probably OK.
5861: You also have exposure issues and the asset is out of focus too, but it has more contrast and looks more in focus at the first sight. I suppose that this made the moderator accept this. In my eyes, it could also get a refusal.
any chance to fix the focus in this frame?
The focus can't be fixed, sharpness can be fixed in limits. Exposure and contrast are no problem to fix (in your case). I wouldn't spend much time on the first picture. The other ones may be fixed and resubmitted, and with luck they will pass. However, just as a matter of fact, flower pictures have a very low sales factor and there are plenty of them in the database. I also have some flowers in my portfolio, so I won't discourage you to edit and resubmit, but it would more be a kind of exercise than a commercial success.
You should also consider the background. The photos are messy:
Bee would probably be better if it was in focus! Or just clone it out in this case.
This would be one major factor in refusal!
5861, is cleaner with no disturbing background! Therefore was accepted.
Practicing your photography and editing skills on flowers can be fun and provide valuable experience; however, as @Abambo has indicated, the chances of ever selling one are very remote. Just to satisfy my curiosity, I searched the database for "red flower". There are more than 5 million!!! So, by all means, continue pointing your lens at pretty flowers, but don't bother uploading them to Adobe Stock (or any other stock agency). It's a waste of your time. Look for more unique subjects to photograph.
Sorry but I stopped looking at flowers. It's unlikely you'll ever sell one. Find other things to photograph that don't have millions & millions of other submissions.