75Mbs means you are using 2.4Ghz, AC68U is a solid router. Moving to routers like AX88U pro or GT-AX6000 only enhance 5Ghz channel but not 2.4Ghz. You need to tell more details. Othersize, a $200 won't help much.
I used 2 weeks of beta, and guest AP gave me trouble. Had to switch back to this version, with "wifi Roaming Assistant" disabled, it has been working fine for more than 2 weeks.
10 months since last June and no firmware update. Asus abandoned this router.
I did not see that and did not know this feature...
But guest AP has been an issue since 21514, disabling "roaming assisntance" helps. With this beta version it won't work.
I disabled Roaming assistant and still 2 Thermostats on guest AP are constantly disconnected with Tx/Rx = 1. I gave up and switched back to 21514 with Roaming assistant disabled. If that still doesn't work, I will go back to 23285.
I did not have this issue before switching to 21514. I tried...