Hi @Fluffhead,
Welcome to the community
We should only use code from an official release of OpenZeppelin Contracts. The GitHub import in your contract imports from the master branch which is subject to change (which can also make it difficult to verify).
If you want to import via GitHub please use a release tag, e.g.:
https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.0.0-beta.0/contracts/token/ERC20/ERC20.sol
Please note Solidity 0.8 support is only in the OpenZeppelin Contracts 4.0 Beta.