Question about income before start date, business closing and leaving France

I have a bit of a weird, specific situation. I earned freelance income in 2023 and did not realize I needed to be registered as an auto-entrepreneur to declare this income and pay tax on it. When I figured it out I immediately took steps to correct it and successfully registered on 05/06. My plan was to declare my turnover already earned last year and this year, which would be around €18,000, in my first declaration to URSSAF.

However, I am also still deciding whether to apply for the RECE visa and stay in France or to accept a job abroad. I only applied for the auto-entrepreneur status to correct my previous error. My visa expires on 22/09. Basically, I am trying to understand the financial implications if I do NOT renew my visa and close down my auto-entrepreneur status when I leave in September.

My first question is:
- I know the VAT exemption threshold and auto-entrepreneur status threshold are pro-rated starting from the day you start your business. Are they also pro-rated from the day you end your business? If yes, is it going to create problems or cause my taxes to go up if I declare such a high sum for such a short period in the calendar year (I think 108 days between the start of my business and the date my visa expires when is when I would shut down my business)

Also, I submitted an ACRE application when I applied for my business because I read a page that said it was “mandatory,” but I assumed I would not get it since I am over 30. I did not check any box in the “situation du demandeur” column or provide related justification. But, I looked on my attestations in my URSSAF account and it was accepted.

My second question is:
- Was the ACRE approval a mistake? Do I need to raise the issue to URSSAF and ask them to take it away?