Change of status from H1B to F2 when resigned from H1b job status

Current Status: I have resigned from my current job and June 12th will be my last day of employment. I am on H1B visa valid until September 2021 and I currently do not have another job offer. My husband is on F1 visa valid till January 2021 with an OPT extension available for 2 more years.

Q1: Should I apply right away for a change of status to F2 visa or can I use 2 months grace period to convert to F2 visa after June 12th and use this period to find a new job.

Q2: If I find a job willing to sponsor H1B can I switch back from F2 to H1B on my current H1B visa valid until 2021 Sept. Or once I convert it will get over?

Q3: If F2 COS (Change of Status) is pending and I find a sponsoring job, can we cancel COS request?

Q4: If F2 COS is pending and I go over 2 months grace period limit can I stay in US until the decision is finalized?

Q5: If the decision is denial, do I have to leave US the same day?

Q6: If after denial of COS status I find a job that is willing to sponsor can I enter back in USA on my current H1B validity?

Q7: Can I switch to F1 from F2 in USA itself?