Provider errors

[soccerarenadev]

Provider is supposed to be optional (according to the docs). However, when not supplying one, I get this error:
Provider required to setup web3

Checking the source I see this:

  customProvider,
  reloadOnAccountsChange = false,
  enforceReadOnly = false,
  enforceReload = false,
  ensAddress
}) {
  if (!customProvider) {
    throw new Error('Provider required to setup web3')
  }

So, it doesn't seem to be optional.

Furthermore, when passing a wagmi or Ethers.js provider, I get "unsupported provider".
For instance, using the default provider from ethers:
const provider = ethers.getDefaultProvider();

Raises this error:
Error: unsupported provider (argument="provider", .... code=INVALID_ARGUMENT, version=providers/5.7.1)