Low transfer rate writing on NAS

Hello,

I have a Netgear Orbi RBK50 running on firmware V2.0.0.74 and an QNAP TS-431P running as a NAS. The Orbi and the NAS are connected via 1Gbit Ethernet via a Switch.

When I connect my laptop via Ethernet with the Orbi, I achieve a writing speed on the NAS of 40-45 MByte/sec. When I connect my laptop wirelessly with the Orbi, the speed drops to 15 MByte/sec. I am surprised by this, as my laptop stands next to the Orbi, is connected with the 5 Ghz channel an ac-mode and claims to habe a Tx Rate of >500 MBit/sec = 62.5 MByte/sec.

Is there any reason, that explains the drop in speed? Or even better: Any ideas to improve the speed in the wireless setting?

Thanks for your help!

PS: Additional question: I saw that a new firmware is available but was discouraged by the instructions for a manual update. When do new firmwares usually become available for automatic update?