My suggestion would be to not submit the DS-260 form now if you plan on leaving the US in July. Wait till you return, then submit the form. I normally would caution anyone on a non-dual intent visa such as yours to also be aware of the 30-60-90 days procedural rule of demonstrating immigrant intent, which is basically to wait at least 60 days after the last entry into the US before demonstrating immigrant intent.
So in your case, I would outrightly suggest you wait until September at least before submitting your DS-260 form. Yes, you have a relatively low CN, submitting the DS form 'late' will not negatively impact your case IMO. If your fear is that KCC may not have enough time to process your form and send you a confirmation letter like they'v done in the past (we don't even know if they will be doing the same this time around), I would say don't worry about it. You can still submit your I-485 package without that confirmation letter, you will have an opportunity to present it at the time of your interview if the IO insists on seeing it. Upon your return, you can use the time inbetween to complete your medical exam and pay the DV administrative fee about sometime in August or September.
Thank you Sm1smom. May I impose further on you? Could you advise what is the implication of the procedural rule? Is it that if I don't wait the required 30-60-90 days before demonstrating immigrant intent and my application for AOS is denied I may/will not be able to revert to F1 status?