Oneplus 65w charger is not compatible with Huawei, because OnePlus and Huawei are two different companies, so their charging agreement is not the same, that is, the fast charge agreement can not support each other, so the Oneplus charger can not be used in Huawei mobile phones, and there is no way to activate the fast charge when used in Huawei mobile phones.
The answer is yes, yes, but not absolutely
As we all know, one plus OPPO vivo real me and IQO belong to the BBK series of mobile phones, so one plus 65 watt fast charger is able to give the same series of mobile phones for fast charging services, one plus mobile phone support pd PPS fast charging protocol, can be compatible with more devices