The boot loop issue was something that seemed to mostly affect LG G4 models. I did see some G3 boot loops around the forums - however, that was a much rarer occurrence. My G3 never boot looped in the 13 months that I used it. The G5 and V10, as far as I know, have only had rare occurrences of boot loop - at least, from the looks of things here in the forums, and in comparison to the G4.
I would definitely recommend the V20 to you. If you are worried about a boot loop, I would purchase a warranty or some kind of insurance on it; and be sure to know what the terms of that warranty or insurance entail, so you are satisfied with your decision.
In the end, you never know - maybe your V20 will boot loop. However, each of us takes a chance when we buy a mobile device, as every model from every line and every manufacturer can develop problems; be they boot loops, water damage, freezing and lagging, or battery issues. But just because those things may happen, doesn't mean that they will happen!
If you want the phone, go for it! It's a great experience, from what I've heard.