If there isn't any sort of bitcoin service that you can use in your country for paying bills, then you're out of luck. You can simply do what most bitcoin-only people do though; sell a bit of bitcoin each month solely for your bills.
Please, what do you advise I do in other to hold at least 80% of my salary in bitcoin?
Use your salary to buy bitcoin after every paycheck, and leave some fiat for your bills. It's that simple.
True, you must think of the bills if you do have. Always reserve for fiat in case of emergency and use your salary for buying not directly in bitcoin. By that you can maximize whether you want to use it for now or save it for later.