Yeah I would say not. With games that do HDR the right way, the difference between 600 and 1k when you are adjusting the sliders is one or two notches before it tops out and you cannot see the difference in the graphical example anyway. With that said though, I would definitely wait until the OLED of your choice ships with HDMI 2.1 at this point - HDCP 2.3 will pop up in your head but that will be for 8k content and I do not think we will see that before you buy another OLED.
For me on the burn in issue, the B9 has some corrections of that so it isn't as impactful. I have a B7 and haven't had the issue yet after 2 years. However, just to make sure (From someone who never buys warranties) I did get the 5 year replacement plan through Best Buy which covered burn in. It was $599, but when spending $2500 at the time on the set, I wanted to make sure I was covered just in case.
The true blacks are absolutely fantastic though. It is going to be VERY hard to go back if I ever have to at this point.
(Looks like the B9 has that, but also G-Sync support) thats huge. B9 on sale at BB right now for $2299. (65")