The problem plaguing the earlier phones was specific to bad soldering. For bootloops in general, there's lots of possibilities both hardware and software related. The number of confirmed V20 bootloops are tiny, and those haven't been confirmed to be caused by the same design flaw. If they had not fixed it, the V20, 30, and 40 forums would be flooded with complaints (not to mention something that critical killing off LG in the phone market), but they aren't. The V20 has been rock solid for me and most other users on this forum. It's still very highly respected for that and the overall design. The 30 and 40 are also highly respected by their users.
I'm not doubting that you know a couple of people that had a bootloop on their V20, but I do question the root cause of it and do not believe your claim that there is still such a critical design flaw inherent in all LG phones.