Hi,
Getting low speed is understandable and mainly because of following reasons
1) You are running 325 in conjunction with Velop (not sure how many units
but usually there are 3). If for some reason 325 is able to listen all 3
non-overlapping channels, there is a chance that 325 will revert to lower
TX power and try to find least congested channel
2) Having multiple brands of APs/Routers in a small vicinity always lead to
performance issues, there will be way too many collisions and retries so
unless you are trying to cover some grey area (dark spot where coverage
from velop is less or non-existent), dont use 325 or any other vendor.
3) APs from multiple vendors cannot work in harmony due to unlicensed
nature of 2.4 Ghz and 5 Ghz. Multiple brand APs cannot be coordinated.