Nonce reuse resistance
The scheme you propose certainly leaks plaintext repetitions to an attacker since the same plaintext is always encrypted to the same ciphertext. You typically don't want this and it can be disastrous if the attacker knows some of the messages.

If you are absolutely sure that leaking repetitions is no problem in your case, you can use an authenticated encryption scheme with nonce-misuse resistance. Note that not all authenticated encryption schemes have this property. If you use a scheme with nonce-misuse resistance, you can even use the same nonce (say $0...0$) for all messages, so you don't need the hashing trick. If it is not, a hash function that is not collision resistant does not make it secure because an attacker can find different messages that hash to the same value, so you will end up using the same nonce for different messages. I don't know whether ChaCha20 Poly1305 together with a cryptographic hash function provides nonce-misuse resistance, but unless this is proven somewhere (or at least some other evidence is provided), you should not assume it.