AURUS BEAST POWER 450W (its very popular in my country and so many people recommend it and other high brands are very expensive)
That is a crap quality PSU.
Found a label of it;
Direct link if image doesn't load:
https://ae01.alicdn.com/kf/S50c7dfccc8ae43ab867f2b6f162b612fs.jpg
From label, you can see that your PSU isn't 450W unit, but instead 354W unit. (Since +12V rail has 29.5A, which: 12x29.5=354.)
And one can not combine PSU rails to magically increase it's output wattage.
For that PSU, RX 580 doesn't happen. GTX 1060 is also pushing it.
Heck, i wouldn't use that PSU to power anything.
So, if you want better GPU, look for better quality PSU as well. Else-ways, it is just matter of time, when your Aures goes "pop", releases magic smoke and fries everything it is connected to (aka your whole PC, including your new fancy GPU).
For a new PSU, good quality units are: Seasonic Focus/Vertex/PRIME, Corsair RMx/RMi/HXi/AXi, Super Flower Leadex Gold/Platinum/Titanium.
Now, i do get that depending on where you live, good PSUs cost a lot. But there are cheaper, mediocre quality PSUs out there that are still far better than the junk you currently have. Those include: Seasonic Core, Corsair CMx/RMe/RM, Super Flower Combat/Legion.
For other options, here's PSU Tier list,
link:
https://docs.google.com/spreadsheet...JWkc/edit?pli=1&gid=1973454078#gid=1973454078
Look for a Tier B unit.