If you want to keep it simple and you already have muffs, then buy a pair of foam ear plugs (they’re inexpensive) and double up. Wear muffs and plugs. This was required in a few areas of the mining operations I was doing OH&S.
We go shooting every week, and I wear these: Howard Leight by Honeywell Impact Pro Sound Amplification Electronic Earmuff (R-01902) that I bought on Amazon about 6 years ago. Highest rated I could find. I have severe hearing loss, wear hearing aids and try to protect what I still have left. You could also double up - wear ear plugs under your muffs, but I find that uncomfortable.
I’ll second the idea of doubling with ear plugs. I use MSR Sordin shooting muffs for shooting, blacksmithing, repousse and museum blacksmith demos. The better (newer) electronic muffs attenuate the loud frequencies and still allow you to hear conversations. If you use ear plugs, just boost the volume to still hear ambient sounds.
One important factor: the ear muffs must seal to your head. Fat safety glasses can degrade that. I use wire frames; others use elastic strap types that go over rather than under the ear cups.
And if you are shopping, you might consider an input jack or Bluetooth capability.
I think it is relative mass proportions. I’ve got a 4"x4" welding angle magnet on a 400 pound anvil. Seems to work. A fridge magnet probably wouldn’t. I’ve seen an inner tube full of sand wrapped around an anvil base: very quiet. I use some very small O-rings as mufflers on my mantle clock chimes.
