Hi, Having set all mob death, A lot of them are dumb :p
I can see few solution:
A blacklist, with a death reason for a mob. But you'll losse all the infos.
or, like some chat mods do, display the death once and add a little counter to it (like on the picture where I spammed "t" 4 times)
Sadly I haven't found one of these mods working with your mod.

Can you say the chat mods that do this text compression so I can take a look?

Yep, there is Chat Patches (but turned out the compression thing doesn't work at all for me in 1.20.1, I haven't tested in .4 or else that seems to have got an update for this matter.

Compat chat (the one from the picture) also didin't work for you mod's messages.
But after I opened this issue I came around Chatutils wich does compact the death messages :)

Still think it could be a cool feature directly from your mod :)
Main benefit beiing that you don't get randomly a big list of stupid squids covering half the screen :p

Oh, so it does compact. I thought I wouldn't "stack" for the same reason as beehives, since while the text is the same, they have that hover event with the entity UUID.
I'm now making a mod for Modfest, so I'll only look at it later