Hi,
It seems like the the ssh command when used with GIT is not using the IdentityFile from your ssh config file. These are two different ssh commands. (OpenSSH_for_Windows_7.7p1, LibreSSL 2.6.5 vs OpenSSH_8.0p1, OpenSSL 1.1.1c 28 May 2019) It might not support the %d syntax there. According to the log you posted, it tries these private key files for authentication:
debug1: Will attempt key: /c/Users/████████████/.ssh/id_rsa 
debug1: Will attempt key: /c/Users/████████████/.ssh/id_dsa 
debug1: Will attempt key: /c/Users/████████████/.ssh/id_ecdsa 
debug1: Will attempt key: /c/Users/████████████/.ssh/id_ed25519 
debug1: Will attempt key: /c/Users/████████████/.ssh/id_xmss 
You can check if the %d is not supported, but changing the line
IdentityFile %d/.ssh/keys/balena_legowerewolf
with
IdentityFile /c/Users/████████████/.ssh/keys/balena_legowerewolf
or
IdentityFile ~/.ssh/keys/balena_legowerewolf
Cheers,