Under engine splash guard 2014 500L

Hi, I apologize if I posted this in the wrong place. I’ve been working on changing the oil in my partner’s 2014 500L. I knew it was more involved than a typical oil change but things keep piling up. I managed to get the oil filter swapped for a new one and a new gasket in place. Then I found out that the last garage that changed the oil not only overtightened the oil cap (took a nice long time to get that off) but they also stripped the oil plug bolt head by over tightening it. I had to pick up bolt extractors and I intend to get it removed today.

The issue I’m here about is the under engine splash guard. I was able to remove the 10mm bolts and the phillips head screws but now I’m stuck on the massive bolts at the back. First, I can’t seem to loosen them. Secondly, I’m worried that those bolts are keeping in place something more substantive. Having to remove this cover to get to the oil pan is not fun.

Any advice to get it removed? Thanks!