How would I flash it? I’m not that tech savvy
To be honest with you, all this get a vega 56 and flash it is not for you.
Buy either a vega 56 or a 64 and enjoy the stock performance don't try messing around with them if you don't know what you are doing.
Their are some good deals on the AMD cards at the moment, with their 50th anniversary promotions. Pick one buy it and enjoy it. Either that or wait for Navi hopefully in few months time.