Growling/Vibrating noise

Hey! I have a Prius 2006 at 300k.

I started having this loud start up noise a month and a half ago, when Toronto was super cold.

The sound seem like it got louder overtime, it is most heard on the drivers side. I've changed the engine filter, oil, transmission, and water pump recently.

Basically even at speed 30, the sound comes on (after the growling noise at startup - car starts to vibrate a bit). The faster I go, the sound is a bit louder. Sounds like the engine/motor is working hard (like on cruise mode at 110+).

Our oil seems fine, but after the oil change, it somehow splashed into our engine filter area.
Everytime I drive now, it seems like there isn;t enough power on the wheels (like it's losing air), still growls at start and growls during the drive (sometime its super loud!). At some point, there's a vibration feeling under my feet (driver side), and now when I drive, it sounds like grinding gear noises.
Only when the engine is in use, it has the loud growling noise. No a/c or heat is on as well.
Not sure if this is needed information, but i'm using a Gen 3 AMG battery (OEM Toyota), it's super hard to find a GEN 2 battery here.


I've checked the engine filter it seems fine.
No knocking noises. No warning lights or anything.

I'm really now sure what's going on. It started during the cold season. Thank you!

*Will update with link for audio

 

Yes that is correct. It basically started In the cold and the sound gets worse after highway. If it is the catalytic, how do I check if its loose?

There was only once that the oil was low. But usually we dont lose that much oil between oil changes. It's usually like half an index finger on the dipstick. That once I was low and didnt realize, but the sound didnt come on til like 1 or 2 weeks later.

 

Would the sound continue even after 3 hours of driving? It basically has the growling noise all the time now. Now its like some grinding gear noise. The sound is continuous unless the engine isnt on and I'm at a stop light.

 

Another thing. It happened when I drove on the highway with a 5.0 cubic freezer in the trunk (A 4 hour drive highway). Then it started to have a super loud sound next day.

https://voca.ro/12khndvohprT This is the starting sound of the car.

Now when I go over some small bump, there seems to be something loose underneath, was vibrating underneath.

 

Yes, I just checked if I had the catalytic converter and it is still there. Is there a way to check if I have a hole in the exhaust system without going to the mechanic and a lift?