I just found out that if you use the latest Putty Key Gen 0.75, it uses ARGON2 for key derivation. Filezilla wont even let you select this private key as usable.
I'm assuming since Putty key gen and Filezilla are probably paired to use most often, I hope this will be fixed in a version of Filezilla.
Example output from the newer 0.75 private key file:
Key-Derivation: Argon2id
Argon2-Memory: 8192
Argon2-Passes: 13
Argon2-Parallelism: 1
Argon2-Salt: asdfasdfasfasfasfasfasfasfasdf
Putty key gen .75 ARGON2
Moderator: Project members
Re: Putty key gen .75 ARGON2
Which version of FileZilla are you using?