TR-004 RAID5 synchronisieren

I have connected a TR-004 to a TS-451+ via USB. Now I have swapped the 4 hard drives one by one. Since the new 4 hard drives are larger, I wanted to resynchronize the RAID5 just like with the TS-451+. Strangely, all the corresponding buttons on the TR-004 are grayed out and therefore cannot be selected. What can I do?

I read on reddit from a message posted by QNAP Daniel (some time ago) that you cannot simply expand the raid o the tr-004 you would need to wipe the data first of all.

https://www.reddit.com/r/qnap/comments/fx7zun/comment/fmtgw9r/

unless this has changed since then.