If you are using the device in router mode, then it seems this throughput is to be expected. While in theory the wifi 5 radio could reach 867 Mbps, real world speeds seem way lower. See here:
If this is a hard to swallow pill and you look for improvements, maybe OpenWrt master snapshot has improved on that front, so you could try that, or do some further digging and find out why and if the problems are fixable. I have read somewhere there is only limited open source support by some of the major chipset manufacturers. Qualcomm seems to be one of them.
The other alternative is to switch to another device. If so, I would recommend to do a quick check in the forum before you procure another device.