I also live in an earthquake area and right now I have 3 wild brush fires burning within less than 30 miles (50 KM) of my home. For now, I still have grid power, but they have issued us warnings that the power could be cut any time to reduce the fire danger in the high winds. But most of the people that have solar power systems are all just grid tie with no backup power. During our last grid power failure, my house was the only one with the lights on. After the power was out for about 5 hours, I started hearing a bunch of generators being started.
Yes, batteries are expensive, but they are truly needed to make a stable power source. PV solar panels are great, but the power output directly follows how much direct sunlight is hitting the face of the panel. The Enphase iQ8 line of microinverters are able to form a local grid and produce power when the grid is down, but there are a lot of limitations. If you look at a typical power output curve for a day, you will notice how the power output forms a bell curve. Here is my power curve from my Enphase iQ7 system for today. This is 16 x 300 watt panels with an iQ7 inverter on each panel.

Each bar is the average power produce for that 15 minutes. You can clearly see there are some dips in the curve. That is caused by clouds going by. And since the bar is a 15 minute average, it is possible the power dips went much lower but for only 1 minute in that 15 minutes. Only 12 of those 15 minute bars stayed over 2,000 watts even though I have 4,800 watts of STC rated solar panels on that system. That is a total of 3 hours, where you could use 2,000 watts.
But it is even wors than that. Any power you don't use as it is produced is just lost. In those 3 hours, we could have easily pulled 6,000 watt hours, but if you were just running a few lights and charging your phone, you threw away the rest of that power. When you have a battery, it will store all of the power from the solar panels and you can use it any time, even at night, not just the 3 hours near noon. And this was on a good day of winter production. Here is Dec 22nd when we had more clouds.
The maximum power hit all day was just 1,600 watts, and that only lasted for just one 15 minute slice. Most of the day averaged under 1,000 watts. You could not even us a microwave oven. With just a small battery, it can store up energy and give you 3, 000 watts still, for a few minutes, even if the clouds are making it so your solar panels are only making 300 watts. If you store that for a full hour, you can run 3,000 watts for 5 minutes. You can't do that without a battery.
The Enphase iQ8 system can easily add iQ batteries later, but they are VERY EXPENSIVE. The cost per kilowatt hour of storage is bad. My iQ7 microinverters are compatible with an iQ8 based battery system, and I did look into buying that, but the cost was so bad. Instead, I went with an AC coupled Schneider XW-Pro hybrid inverter, but I will admit it was certainly not perfect or smooth to make it all work.
A much easier option would have been a Tesla Powerwall2, but at the time, no one would sell me one for my existing Enphase solar.
What brand inverters are available to you? I know there are Growatt and Deye hybrid systems that can use a very small battery or even run with no battery. And then you can add more battery storage later if you find you need it. Even a tiny battery can make a huge difference as it will run the inverter to make stable power for a couple minutes as clouds move by. It can also supply a current surge like the compressor starting in a refrigerator. Solar panels directly just can't provide any surge current. Adding capacitors, which is what allows the inverter to work at all without a battery, will help a little, but you just can't stuff in enough capacitor to last more than a couple seconds, let alone minutes or hours like you get with batteries.
I have no idea if this is any good, but I found this hybrid "48 volt" battery inverter that an work on the Japanese 100 volt power grid. This one is rated at 5,000 watts and can accept over 5,000 watts of solar panels at up to 500 volts. That gives you a lot of options or solar panel choices.
Does this sound like what you want? If you can get the brand and model number for a nuit, I can try to look up a manual for it and see what it can do.
6,500 KWHs a year is a bit less than the 8,000 we used here but seems very reasonable for a typical home. To be able to safely run for a few days off grid, I typically recommend having enough battery capacity for 2 days. And then have enough solar panel to be able to charge it in just one good day. For your use, I would recommend about 300 amp hours at 48 volts. There are now batteries what that much capacity in a single case, but they are big and heavy. Most typical "server rack" type bateries are still 100 amp hour each, so you use 3 of them in parallel. There are a few on sale here that go for about $1,000 US dollars. Not cheap, but not crazy either. And you can probably start up the system with just 1 battery and buy more later if you decide you need it.
For solar panel, we want to charge 15 KWHs in a day. Have you looked up how many "Sun Hours" you get in a day for each month of the year? Where I live, I get 3 to 6 sun hours a day depending on the time of year, but it can also drop under 1 sun hour in bad weather. A good safe estimate to use here is 3 sun hours and most days will do more. Today, my system did 15 KWHs from 4,800 watts of panels. That is just a bit more than 3 sun hours. 1 sun hour on 4,800 watts of panels produces 4,800 watt hours of electricity. This is pretty close to what you would need. Round it up to 5,000 watts of solar panel, if you can fit it and aim them at the sun towards the equator.