New Pace 5268AC Gateway having trouble settings up an access point

So, I just received this new modem/router with the new gigapower service. Initially I've been having terrible, terrible luck with adding anything to the network that isn't directly connected to that router itself.

Initially attaching switches would cause the router to hard lock.

Now I'm having issues with my Asus router that is put into access point mode for coverage.

I've seen many other people having success with the new Pace 5268AC router and attaching APs to it. Anyone ever seen the network just break due to adding an access point along the lines? I previously had the NVG589 modem router and had 3 APs and around 5-6 switches in multiple places in my home and never ran into any issues.

If anyone has any explanation to that, I would appreciate it.