Yes, you can record 4K videos with Nokia 7 Plus at 30fps.
No. Nokia 7 Plus does not have the notification light. But it does have the ambient display, so you will always get alert on the display.
No. Nokia 7 Plus does not have a dedicated memory card slot. It has a hybrid sim slot. So, you can use a MicroSD card and a sim card at one go.
Yes, Nokia 7 Plus does have the OTG support.
Great battery life, immersive display, solid design, and software at its purest, that's the Nokia 7 Plus for you.