Bitcoincore 0.21.2 - SHA256SUMS.asc

Hi,

I tried to verify the SHA256SUMS.asc form Bitcoincore 0.21.2.
I get

Code:

gpg: Signature made Wed 29 Sep 2021 06:26:46 BST
gpg: using RSA key 90C8019E36C2E964
gpg: Can't check signature: No public key

When I fetch the Key form hkps://keys.openpgp.org I get

Code:

gpg: key 90C8019E36C2E964: new key but contains no user ID - skipped
gpg: Total number processed: 1
gpg: w/o user IDs:1

I understand that it has something to do with the RSA-format but I can't figure out how to receive the proper public key in order to verify the SHA256SUMS. I also collected some public keys form contributors of this version but it didn't work.

Help is very much appreciated.