Then, the curve your ECC key uses (ed25519) is not supported by the applet. Only NIST-P and Brainpool curves are.
That seems like…a massive issue? Guidance for Choosing an Elliptic Curve Signature Algorithm in 2022 - Dhole Moments
TL;DR Ed25519 is great. NIST P-256 and P-384 are okay (with caveats). Anything else is questionable, and their parameter selection should come with a clear justification.