Mysterious intermittent rattle/scraping noise

I have a 2010 with 155k miles on it that has been experiencing a weird rattling noise for the past month or two. The noise started the same day I bottomed out on some ice (unfortunately) and went away for a few weeks but now happens nearly every time I drive. It sounds like hard plastic scraping on something or a something hitting bicycle spokes, almost like a rat-tat-tat. The noise usually doesn't start until I've been driving for 15-20 mins and I notice it most at 10-15mph. It only lasts for a second or two each time, and seems to just happen while I'm accelerating - when I take my foot off the gas, it stops. To me it sounds like it's coming from the front driver's side of the car but I had my friend listen to it who said it sounded like it was coming from the middle, almost below the center console.

I've brought it to a shop by me who have tried to secure any loose plastic, but I'm not sure they've investigated anything beyond the undercarriage. They think the next step is trying to replace the piece (I assume splash guard?) but I wanted to see if this is a noise anyone else has experienced first. I'm very much car illiterate so any thoughts are appreciated!

I took a recording of the sound but am having trouble attaching it, I'll try to add it in the comments. Thanks!

 

the noise happens at the beginning, and again around 14-15 seconds

 

Thanks! I haven't personally investigated the engine cover closely but I've brought it to a shop 2x who are pretty confident they've secured as much as they can (it is somewhat cracked apparently). I noticed one of the fender liners was missing a screw so they replaced that as well, but they look fine otherwise (although I haven't inspected them super closely).

I guess I'm just trying to figure out if this sounds like a serious/bigger problem or like a broken piece of plastic based on the noise & symptoms (especially since it doesn't start until I've been driving for awhile, and only while accelerating)