I've always felt that Oneplus is a brand that I should like on principle of having clean software with barebones but powerful hardware, but in reality, every single Oneplus phone I've seen always had some sort of big BUTs attached to them, so buying Oneplus always feels like settling.
Take the Oneplus One for example, that sandstone textured cover was THE most creative material I felt a phone could have had, and I'm honestly shocked nobody has ever done it again. But along with that of course, comes with the cringy "smash your phone" marketing campaign, the half-hearted attempt to distance themselves from their parent company Oppo, the whole software mess with CyanogenMod/OxygenOS, etc.
Had a Oneplus 3T for a while, same deal: Great phone when it works as intended, but they raised their price without making the phone better, and the inexplicable random restarts/battery drain is so irritating, never had another phone that does that.
Recently they've dropped all pretense of not being Oppo and abandoned their core audience, choosing to have the "courage" to drop the headphone jack. Mediocre Chinese phones with flagship specs are a dime a dozen, I just don't see a reason to buy them anymore.
My friend recommended the brand saying he never had a problem with it and it was as fast as the day he got it. My wife got one because her Pixel 3 died (apparently a relatively common thing for that model). Then after my wife got one my friend started complaining about his phone and my wife didn't like her new phone. Then he got a pixel lol. Then I got one. It's a nice phone. The Pixel 3 was my wife's favorite before it died. So 2 years later we ditched the one plus for a new Pixel for her.
It seems like one plus used to be a good brand and maybe my friend had some loyalty still or his phone coincidentally started to slow down right after he recommended it lol