Taktikal 1600 issues

[swfl_extreme]

Hello wireless folks. I need some help. I am now on my 3rd router from this company TAKTIKAL. It is this one: https://taktikalnetwork.com/products/1600atv-5g-pro

The ongoing issue that I am having is with carrier aggregation. When I first reboot the router (or even when I go into Modem/Miscellaneous and disconnect/reconnect current modem) it will aggregate up to 4 different bands in my area and the DL speed can get up to about 120Mbps. Unfortunately, this doesn't last, and it will drop back to a single band and the speed drops to about 20Mbps. It doesn't matter how much bandwidth demand I put on the connection, it will not re-aggregate until I reboot or disconnect/reconnect.

The amount of time it aggregates varies, but the longest is only about an hour or so. I am using an AT&T Unlimited Tablet plan SIM.

The current firmware on the router is GoldenOrb_2024-07-22

Any help with this would be greatly appreciated because I am at my wit's end.

[swfl_extreme]

Supplemental information since nobody is responding. I am using this antenna - https://www.amazon.com/gp/product/B01NB ... UTF8&psc=1

Here is a screenshot from the cellmapper website that I have annotated showing the location of AT&T 4G LTE towers near my house. There are NO AT&T 5G towers nearby. https://tinypic.host/image/ATT-4G-LTE-Towers.D68BVz

These are pictures from my roof antenna showing the amount of trees on the south side of my property (trees in all directions honestly) https://tinypic.host/image/IMG-3721.D682t2
https://tinypic.host/image/IMG-3720.D68DEU

Does anyone have any suggestions? TIA