Hardball with Deloitte using my M&A boutique?

I just completed the Winter 2022 internship at Deloitte in the audit dept.(Jan-Mar). I did prior recruiting work and luckily got an internship at an M&A boutique for the period of late March through May. I come from a non-target and am only an accounting major, so this is good.

I already got the verbal FT offer from the partner, and Deloitte will want to know my answer sometime soon. I know I can stall them for a bit, but going forward:

1. Should I use my M&A internship to try and get a second internship at Deloitte M&A for the summer?

2. If yes to 1, how should this be done?

   • Do I bring it up later this week when HR calls congratulating me with the audit FT, telling them I'm about to start an M&A internship and would like a summer one at the subsidiary DCF, LLC (Deloitte Corp Fin, LLC)? These guys supposedly do actual M&A deals. Risk - That these guys only hire the M7 kids who couldn't hack the BB bank interviews (gist of what I read, maybe wrong on this).
   • -Do I shoot lower and ask for M&A Advisory position where they do FDD and accounting support for deals? Risk - that I'll get stuck here in accounting support for M&A and not actual M&A.  
   • -Or do I wait until closer to summer by delaying my acceptance of the Deloitte audit offer, until I have more concrete experience to then tell HR what's going on? Risk - It's too close to summer for them to place me in either DCF, LLC or the M&A Advisory line.

3. If No to 1 then I would go through this boutique M&A internship, seek another IB boutique for the summer (I got another in talks so far), try to get into Deloitte Corp. Fin, LLC for full-time next year.

Why Deloitte? I like their brand and frankly the Middle Market of the B4 in their Corp Fin lines sounds doable for my background.  I feel with the job market as is, that I have a little pull since they invested in me.

I have to consider these paths because I've already been told that an internship in whatever M&A line of Deloitte is not happening for us audit interns. I recruited for the boutique for just this scenario as leverage in talks that I may have and just in case they didn't give me a second Deloitte internship in M&A outright. And yes, they offer M&A advisory and Deloitte Corp Fin. internships for the summers.  But I need advice on how to proceed.