Possibly got leak, how old is the aircon

Outside unit needs to be cleaned as well

how old is the AC? When is the last time you have technician to service your AC?

You dismantle the whole indoor unit for cleaning or you only dismantle the plastic casing & cleaning the cool & blower by pouring water on it?
If it's latter, better ask a proper aicond technician to do a through cleaning, most likely the cooling coils are clogged

Outside condenser also need to clean, no clean can't dissipate heat good enough overall pressure high will cause not that cold inside and high current power usage.

Top up gas if there is a leak. Now a day technician found not enough gas, they just top up only. Never check where is the leak. If they fix the leak, they lost future business. Finding leak is also very tedious.
If 10 years didn't dismantled the pipe joint then your problem most likely is not leak, if it's leak then possibly the outdoor coil or indoor coil corrosion which is wasting money to repair.
If not leaking then there are many possibilities. Indoor thermistor, outdoor thermistor, outdoor fan motor, capacitor or even the compressor.
If AC is 10 years old, my advice is to replace a new inverter AC (if yours is non-inverter).
Did your AC got any light that blinking? You can search the manual to see the fault code from blinking light.

I just chemical cleaning for my 10 years old ac also. The technician dismantle wall unit to wash filter, coil and fan separately. Also washed the outdoor unit and top up gas. From the need to set 18c , now only need to set 24-25c and it's cooling faster.

Only cost me rm160, regretted didn't do this earlier lol

Same like me, just did a full aircond service for only Rm160, coolhero. They clean up the indoor unit, outdoor unit using chemical, and top up gas. Now faster cooling

Yes, rm160 all in

Go facebook search for JC air cond Eng

The best part is, they dismantle the wall unit to do the chemical cleaning not do it on the wall.