After updating my TP-Link Deco M4s to firmware v1.5.8, I've encountered persistent Wi-Fi issues. While my wired PC maintains a stable 500/500 Mbps connection, Wi-Fi devices experience intermittent slow speeds. Traditional fixes like running a "Network Optimization" scan via the Deco app have proven ineffective.

I've also tried various troubleshooting steps from TP-Link's support forums, such as disabling UPnP and SIP ALG. These measures offered only temporary relief. Despite multiple scans, network resets, and even contemplating a firmware downgrade, the issue persists.

In desperation, I reverted to my old Archer C5 Router, using the same SSID and password. Surprisingly, the Wi-Fi issues disappeared. To address dead spots in my home, I connected the Deco to the Archer in Access Point (AP) mode, which seemed to be working well for two weeks or so, but today the Wi-Fi network slowed down to the point of becoming unusable and attempting to run Network Optimization scans resulted in errors in the app, stating that the scan could not be performed or at times stating that a Deco Unit could not be found.

I'm baffled as to why the Deco, which had been reliable for 2-3 years in Router mode, suddenly became problematic, then seemed to work in AP mode for 2 weeks and then once again become even more problematic - without any changes to the network from my side. Has anyone else experienced similar issues with TP-Link Deco Wi-Fi? Am I overlooking something obvious?