It seems that "Decryption" is the name of their company. Decryption-issued assets (capital D) is just the company issuing the assets, of which TLchain is one.

Typical crypto jargon bullshit but doubtful that they're brute forcing wallets (or that they would be telling people if that were the case).

No, it is your job to explain to us why you are making this claim.

The whole thing you linked is from a PR firm. They had to issue a disclaimer at the end.