Even death wish is easy with a good build. The trick is to never stop shooting as well as being in cover and not exposed
Mayhem is very easy with a good build and is totally worth it. If u dont have any experience on some heists dont try dw or ds. The heist i suggest is mayhem on a cook off with a hostage taker build, it will give u like 3m xp on 20 minutes
Ffs sto flexing for heists on mayhem or above. I am like III-100lvl and i have the one down mask.