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18-22 is correct for 12vdc. Theory is that it's never going to run at 100% efficiency. Slightly hazy day, loss with every foot of wire distance, loss with every connection, morning/afternoon vs high noon etc. Charging voltages for a 12vdc battery are 12.7 - 14.3, so with inefficiencies, 18-22 gets you right in the ballpark. Perfectly clear day at high noon and the panel output will be close to those ratings on the back. The charge controller handles the conversion to optimum charging voltages.

FYI a fully charged 12vdc battery should be 12.7 volts.
12.0 volts is about 80%. (don't want to go much lower)
Run them down below 11.8 volts on a regular basis and you will kill them quick.(inverters etc will auto shut down at 11.8v to help prevent battery death)

200 amp hour is a lot for 100-200 watts of panel. The 100 amp hour battery ought to do what you want just fine.

BTW, we lived off grid for 5 years using a 320 watt, 12 volt solar panel setup with 4 GC2 golf cart batteries which is about 200 amp hours. We made those batteries last almost 10 years which is pretty good for GC batteries and being first timers in solar. Everyone says newbies kill their first set of batteries in 2-3 years.

I still have the panels and was looking at Renogy charge controllers and batteries just a few days ago. We had a Xantrex C40 charge controller which are supposed to be bullet proof but it up and died. Died the day before we had electric service, pole and meter installed.

From Renogy:

How many panels would I need to charge a 200ah battery?

If you have a 200ah battery, only 80% of that is usable due to depletion limitations, so you really only have 160 amp-hours of energy to draw on. If you learn that you typically can last two days with energy from that battery, that means you consume 80 amp hours a day.

Based on the earlier calculation, a 100 watt panel will produce an average of about 30 amp-hours per day (based on an average sunny day). This means you would need three 100 watt solar panels or one 300 watt panel to fully recharge your battery on the average day.

https://www.renogy.com/blog/what-size-solar-panel-do-i-need-to-charge-a-12v-battery/

“We had a Xantrex C40 charge controller which are supposed to be bullet proof but it up and died. Died the day before we had electric service, pole and meter installed. “

We talked about this before, but lived off grid for over 10 years ourselves. And we lost a couple charge controllers and inverters from lightning striking within a hundred yards. One inverter was tested to work and new as a back up and the EMP field from lightening hitting next to the house killed it while it was in the closet not hooked to anything. lol

Close lightening strikes can kill controllers and inverters.