After the update, QoS no longer functions as intended.

The exact problem is that QoS is working when I enable it, but after some time it stops working and I notice big latency when testing the network... so almost every day I need to go in admin panel to disable and then re-enable the QoS in order for it to work.

I observed similar problem with QoS not working in previous firmware versions and technicians assured me that it was fixed - https://community.tp-link.com/en/home/forum/topic/840532 (in this case, re-enabling didn't do anything, so it's not completely the same problem).