What SAT score should I send to colleges?

Hello! I am a rising high school senior that is planning on applying early action. I took the new SAT with my class in April, and ended up getting a 1280 composite with a 690 in CR and a 590 in math. I retook and unfortunately did worse on the June SAT, however, my essay score is significantly better. I got a 1250 composite with a 660 in CR and a 590 in math. Even though I’m very disappointed in my composite, I was considering sending both scores because of the improvement in my essay score (7,4,7 to 7,7,7 or 18 to 21 out of a possible 24). Would this be a bad idea? I am aiming to get into the University of Michigan (I know this is somewhat of a stretch but I am instate and have other qualities besides my test scores that align with the school’s standards, so I think there is still a chance). My other option is to send one or both of those scores and to retake in October. Lastly, I took the ACT last February and got a composite of 26. After taking the new SAT for the first time and seeing that my score was better than my ACT score (a 1280 converts to a 27/28), I assumed the SAT was just better for me. My new score of 1250 converts to a 26. Should I try again with the ACT as well?

So my questions are…
Should I submit both of my SAT scores or only the one with the highest composite despite the improvement in my essay score?
Should I retake the SAT in October?
Should I retake the ACT?
Thank you very much!!

Also, should I take any SAT II tests? I got a 4 on APUSH and AP Lang, and a 5 in AP Gov. I know that UMich does not require these scores, but in light of my SAT scores I was thinking it could potentially benefit my application.

Send both. That difference in score is normal variation IMO. And they will look at SAT IIs if you send them.
https://umich.custhelp.com/app/answers/detail/a_id/549/~/sat-subject-tests

You should try the ACT, the content seems to be easier; it is a test of timing and strategy.