Multisignature ed25519 (m of n)?

Question

Cryptography

There is a system based on ed25519. I would like to get a multi-signature with minimal refinement, the size of which does not increase with the growth of participants (the number of participants is thousands), the public keys of all possible participants are known at the time of signing.

At first I looked in the direction of BLS, but they need a separate curve, with separate keys. I don't want to expand the code base too much.
If I understand correctly, then ed25519 is a kind of Schnorr (correct me, I'm not a cryptographer), and if I'm not mistaken, Schnorr signatures just allow you to aggregate many keys into a single signature. Again, if I'm not mistaken, this happens due to the Merkle tree from public keys

. I would be grateful for a description of the algorithm from the technical side and not in general terms, or a working example in some language.