GL-X750 v2 EP06-E very low Zerotier speed

I am getting very slow speed if the router connected to the zerotier network, <1/10 of normal speed (as on picture below).
The issues does not come from zerotier nodes, i have full speed if i use zerotier client directly on a pc or on my phone.

ZeroTier is pretty CPU expensive. What does top or htop says while running it?

up to 90% CPU load on speedtest.
There is no hardware acceleration possible for zerotier?

I ended up switching to Beryl AX+huawei modem, where zerotier seems to have hardware acceleration, where is no speed drop.
So i have X750 for sale now