RD, can promise you it's not that with the G5 - that's generally older guard LG G-series phones that had consistent issues from what I remember. Between 3 different people in this household using one, I've experienced/worked with 5 different G5 model phones now (a few refurbished replacements to be forthcoming - but the replacements were for (1) a DOA initial refurbish that had to be sent back and (2) one with GPS that stopped working that had to be replaced - the original was a day one release purchase and was after just over 2 years of usage). Not one of them ever had a bootloop issue. The only thing that came close to that kind of behavior with any of them ended up being the OEM battery going bad after a long time, and replacement battery always made it right as rain. Games have never once caused a hiccup on any I've used either.
The issue at hand here literally only manifests itself with certain select media apps. Grabber added Youtube Red to the mix which I wasn't aware of, but Google Play Movies/TV, Movies Anywhere and Hulu will all do it consistently minutes into whatever you start watching, and only when engaging those streaming apps - and do it every single time, though varying degrees of length into content viewing (varies by a few minutes).
Meanwhile, Amazon Video, Netflix and Dish Anywhere app, you can watch whatever content you wish for hours straight/non-stop without a single hitch.