Isn't the 5X in the same line of phones affected by the LG bootloop issues? https://en.wikipedia.org/wiki/LG_smartphone_bootloop_issues#...
Yup, had the same one. I disabled the big cores and it "fixed" it for a long time but then it started looping again. Then did a reflow and it fixed it for a month before it died for good. I was really hoping to keep that phone around as a cross border phone.
And this might not be an issue for everyone but fact is that in my own circle of friends I know of three Nexus 5X phones that have died to hw failure. And one that is acting strange.
But I personally still have my old 5x with LineageOS and no issues at all. I love it.
What I would go for is one of the phones that came with stock android 2-3 years ago. Buy it used it perhaps from a re-seller that still has one in stock.
Pixel for example has a really nice feel in my hand and is pretty cheap.