You can look up energy labels.
Modern full-size fridge is 1500 Wh/day.
Microwave efficiency doesn't matter (few minutes a day), but power draw is about 1.5x it's cooking power, maybe 1500W for 900W cooking.
Induction motors need 5x current to start. Fridge label includes defroster element, probably runs on 200 to 400W, starting needs 2000W for a second.
Your AC having trouble with 120V 15V from utility is an indication it needs more. Look at the label.
Other than A/C, a 2000W sine wave unit might run things. A heavy, transformer based inverter (low frequency) of 3000W with 6000W surge, or larger would be better. Inverters can be $500 to $5000, differences in performance and quality.
In the summer, if your panels are tilted, can get 5 hours or so effective full sun per day (search on line for your location.) So 20,000 Wh would be 4000W x 5 hours. Panels put out less than rating and electronics less than 100% efficient, so 5000W of panels might do it, if you have room to fit them. I can buy 5000W of panels for about $1500 on the used market.
Need a charge controller, unless built in to inverter. They run $200 to $1000.
Batteries can get very expensive, or DIY can be cheaper but you can screw up and wreck them.
Having batteries for 3 days without sunshine would be excessive $$, get a small generator to help.
A 20kWh battery might cost $5000, more or less (some name-brand lithium cost much more.)
If you only have enough battery for one night, cost gets closer to $1000.
Your power consumption figure of 20 kWh/day is probably higher than a modest home. A/C can be a big consumer in some locations. You may be able to reduce consumption considerably and have a smaller system.