RS700 lacp/lag connection to GC510P is very slow

in a previous thread we established

• my ISP had a amp in place that did not support 3.1 hindering upload
• my street line even with the amp delete was +11dbmv, to mitigate this a splitter was put in to put a -7dbmv tax on the line brining it to in spec of +4dbmv
• the above remediations resulted in the CM3000 cable modem running clean and via direct connect laptop speeds yield correctly at 2000/300
• next i had a issue with the rs700 getting the correct down load but getting only 75 upload, this was found to be QOS calibrated before the coax signals where corrected and did not dynamically recalibrate. disable of QOS resulted in restoration of full upload speeds from the router and the router internal speed test of 2000/300
• from the above we know that the ISP\cable modem\router are in good working order to provide the expected performance

next step of my isp upgrade is now to get that multi gig connectivity to my switches

• i do not have multi gig switches i have GC510p's these are 8port 1gb ethernet, 2port 1gb sfp
  to deliver down the 2000/300 ISP speeds i will need to lag/lacp ports 1 and 2 on the rs700, i will then need to lag/lacp ports 1 and 2 on my primary gc510p
• the second gc510 is connected to the first one via the pair of 1gb SFP connections running as a 4 port lag, this is proven as working as expected
• the only devices on the ethernet network that supports 2gb connectivity is the windows 2022 server running a nic team of 2x1gb lacp to ports 7 and 8 of the main switch, and has been proven to be able to ingress and egress 2gbs
• for the purpose of this testing the second switch can be ignored
• both of the drops down to the patch cable have been tested via laptop connection to the router and the drops each get the expected speed individually

When i tried to setup lacp on the rs700 and lacp the main gs510 is that the download speeds i see start at around 500 and then bleed off to about 300. if i unplug one of the drops speeds will go to 900~ as expected for a single feed, if i then plug back that one and test again we get the 500 bleed down to 300, reverse now unplug the opposite drop and back to 900~

if i have tried to do various scenarios, they all either result in 900~ or 500 bleed down to 300. i have also tried to experiment with STP to see if that makes a different, but observed no change. i cant not find QOS anywhere in the insight portal other then for vlan management, everything is flat all on one vlan and igmp snopping is disabled