no noise on any of my magsafe chargers

Noises while charing is a common problem, but it's not normal. I'd return it for a refund and buy a different one.

Apple Silicon cases are very nice but they are not durable. You can get third party ones that last longer and cost less (but, they usually don't feel as nice in the hand).

Avoid the Apple silicone cases unless you’re getting a discount on them. Get a third-party case that supports MagSafe.

I got an Apple silicon case for my 12 Pro, my girlfriend got one for her 13, my dad got one for his 12 Pro Max. All three fell apart rather quickly. My dad also had the Apple clear MagSafe case for his 12 Pro which broke in multiple places. I now use a Spigen slim MagArmour case, my dad uses the same once he upgraded to a 14 Pro Max. My girlfriend uses a clear magnetic case by Speck. All are in perfect condition still after a year of use each. My girlfriend, dad and I all have physical jobs of varying degrees. My mom also uses a Spigen case for her 12 Pro Max (the exact phone my dad had before the 14 PM) and has had no issues, though it’s worth noting she’s got an office job and she’s not at all hard on her phone cases.

When I was on android, I always used Spigen cases. I think I’ll stick with them when I upgrade my phone this year. I’ve also been tempted by Mous cases as I had one before which I quite liked, but they’re quite a bit more expensive than Spigen.

I use an Apple MagSafe in my bedroom and a 3rd party in my car. Neither make a whine. The noise you hear is likely a capacitor that’s about to die.

I bought the original silicon case for my SE 2020 and it was falling apart rather quickly. Cheaper Amazon alternatives lasted much longer for me. I won't ever by original apple cases again with the experience I had.

This is the one I am using, you have to source your own MagSafe adapter (which aren't too bad now) but I like the build quality and price on this.

https://www.amazon.com/gp/product/B08X4G9RQ2

I don't usually use Apple Silicone cases but my wife has and she liked it.