A slang term originating from East London.
Something described as being "straight up raw" or more generally "raw", entails the described to be difficult, challenging or overwhelming to overcome and is sometimes, but not always accompanied by initial expectations of ease.
The use of "straight up" typically entails it being more difficult than if it was just "raw"
"I was attempting the CompTia A+ exam - it was straight up raw"
"I tried to play Bloodborne after all the hype - man that game is straight up raw"