technicolor DGA0122 with Mercusys halo h50g mesh wi-fi

got an issue, which is on my home LAN
a week ago I got fttp from brsk installed.
the connection is fine reaching expected speeds and pings are low.
the supplied router is a technicolor DGA0122.
I already have a mesh Wi-Fi system covering the house mercusys h50gp.

the problem lies on one of the LAN networks. both the router and mesh system generate their own LAN ips dynamic. and have their own set of numbers. (left them as they are default configured)
I set the mesh system to see the router wan ip, so everything would get through to the outside wan.
also set on the network google DNS in all devices/computers and the mesh/router.

problem is I get blocked and stopped with the router not liking something from the mesh system and it thinks it could be a denial of service (DOS attack)
so it blockstit for a sec every few minutes, so streaming gets interrupted or a site won't resolve for a few secs.
I don't know what causes it.
need help to eliminate the issue from occurring.
took a screenshot of the router log showing the problem
https://photos.app.goo.gl/z53vJ423tH8vkVmx7
all help appreciated.

You could:

1) Connect the Wan port of the h60g directly to the ONT instead of the DGA0122. You would need configure the h60g to use the same connection details as the DGA0122 was using.

or

2) You could leave the DGA0122 in place and then disable DHCP in the h60g and connect its LAN port to the a LAN port on the DGA0122. You should change the LAN IP address of the h60g to an address in the same subnet as the DGA0122 uses but outside the DHCP range.

Thanks.
2nd solution seems the way to go.
I'll give it a try.

Good luck!