Septic systems already have enough bacteria to treat the wastewater so adding additional bacteria or enzymes won't really help. If the tank is not functioning properly as it hasn't been pumped out or you are flushing things that destroy the healthy bacteria, your best option would be to desludge

Smell issue?

Then you  should be looking for effective treatment to seal the septic tank cover properly and effectively..

Ur house old one or new one?
Old low cost house? 14 x 55 ones?

If old low cost, septic tank is small, and if ur household a lot of people, very fast full.

If new a bit one bigger house, then bigger a bit..

Latest one new township is integrated

Since it is kampung house, i believe got a lot of vacant land here and there i guess.

Only solution is dig another bigger and deeper septic tank beside the current one, and join them together, however, open another hole for suction on the new big and deeper one... deep big deep deep so can tahan 8 to 10 yrs..

And then, from the new one, can do 1 small opening for overflowing water to flow into drain..
So once u detect the water overflowing out ad, then is time to pump

All tipu one la. U keep flush flush flush, water going to be more and more one.. how water evaporate? Only through heat

Like this is good normal working tank..
Maybe you pour some fermentation stuff inside lo.
Like probiotic, heavy femented stuff, wine, beer.. let the bacteria sendiri grow inside