Is it possible to online upgrade my RAID capacity while using fewer but larger disks?

Scenario: I have 10x 8TB HDDs in a RAID 5. I want to online upgrade that with 16TB HDDs.

Given that they are double the size, could I first only replace half of it, so 5 disks, since that's the same size as the 10x 8TB, or do I have to replace all 10 of them immediately?

Only found this article, but it doesn't seem to mention a scenario like this: https://www.qnap.com/en/how-to/tutorial/article/online-raid-capacity-upgrade

Reason why I'm asking is, well, 16TB disks are expensive. This way I could distribute the cost over multiple months.