Thanks for the warning. While with Verizon, I've had three phones, a Blackberry, Samsung S4 Note, and Samsung S7 Edge. None were purchased directly from Verizon as, at the time, Costco, Target, and Best Buy (respectively) had had much better deals. I see none of these better deals now.
After having been assured by several Verizon reps that I'd have no problem activating and using an international phone on Verizon, I'd almost bought a Galaxy S10 Plus. At the same time, I must say that both sellers warned me that they would NOT work on Verizon. So, at the end, rightly or wrongly, I've chickened out.
Now I'm hoping that, as 5G phones become more popular, or maybe around Black Friday or Thanksgiving the prices will drop.