RICOH officially recommends that you plug the camera into your computer to charge it. I haven’t seen a recommendation from RICOH for a wall charger that I can remember.
I believe that this is a situation where you have to take the risk on your own.
In my personal experience, I’ve used dozens of RICOH THETA cameras with wall chargers and have never had a problem. It’s possible that some chargers can cause damage. Your best course of action is to ask people what they are using. For example, a community below posted on his experience.
FYI, in my tests, I’ve never been able to get more than 0.41amps current to charge the THETA V. This is some indication that a 500mA mobile phone phone charger would be adequate. There’s likely no benefit from pushing more current to the THETA V and would increase your risk. Though, the internal power circuit in the camera should cut down the current, there is a risk it doesn’t operate as expected.