QUOTE(XPS @ Mar 6 2018, 12:53 PM)
The main reason for the AC86U is the Broadcom BCM4366E chip revision which fixes the known 5GHz issue. Most of my devices for many years now run 5GHz since 2.4GHz is pretty much congested.
Get where you are coming from, the 1300uhp is at a good price/performance. Just that have a high expectation of network stability, hence the choice for a faster processor, more memory etc with the AC86U.
Networks are meant to be setup and forget, not managed at least for the consumer end 
the bolded has been my experience.
used rtn12hp_b1 for 4 years, all good up to 50mbps, non-gigaport, 2.4ghz.
with 100mbps, i had to change... to rtac1300uhp... using a mix of 2.4 and 5ghz... 14 devices in a typical 2 storey house.
both were bought at a local store, preinstalled, go home, plug n play... both excellent for what they do.
never had to tweak anything. except update firmware.
i hope u will find the root causes to the yr problem soon, cheers.