Does it supports eddsa algo

[yashsisodiya]

{
  challenge: 'IMpu7X3u1icaawtEF8Oae55febJbABXG0P9tPY8bc_U',
  rp: {
    name: 'Example Corp',
    id: 'localhost',
  },
  user: {
    id: 'AAAAAgAAAACrywvje',
    name: 'Test 64',
    displayName: 'Final64',
  },
  pubKeyCredParams: [
    { alg: -8, type: 'public-key' }, // EdDSA
  ],
  authenticatorSelection: {
    authenticatorAttachment: 'cross-platform',
    userVerification: 'required',
  },
  timeout: 60000,
  attestation: 'direct',
}

in response I am always getting -7 algo public key

[MasterKale]

Many WebAuthn authenticators only support -7 (ES256). Some security keys support -8, but when they don't they'll use -7 instead. Specifying only -8 in your public key credential parameters is just a preference, not a hard restriction as you're seeing by the fact you still get a response back.