Linksys MX5500 WiFi6 Mesh

I am also a little confused. Is all your Apple equipment still a part of your network? And if so, how?

Speaking in very general terms, if you changed your router and relegated the Apple devices to clients of that new network then they may need to be reconfigured or reset. Describe how each of them are connected to that new network: Ethernet, or...?

All recent Apple AirPort equipment supports HomeKit and remains fully supported despite having been discontinued. Being a communication protocol HomeKit does not require any particularly specialized network equipment, but nevertheless I understand you're experiencing trouble with their replacements from Linksys.

In situations such as yours the way to go about fixing it is to simplify the network as much as possible. At the extreme limit it to one device, confirm the network is performing as expected, and then add the switch. Progressively add more equipment, and keep testing.

Obviously this is tedious especially if things work for only a limited amount of time; after all if it takes eight or more hours for a particular problem to become apparent, troubleshooting will take several days at best. You could of course buy a replacement 8-port switch as you suggest and see if that resolves the problem, but a part-substitution approach to troubleshooting gets expensive. I have had switches that have had one port go bad while all the others work... 🤷🏻‍♂️

I only wish Apple would come back to the market place with a smart wifi solution.

Discontinuing the AirPort line of equipment is one of Apple's most puzzling decisions. I can't remember the last time I had to reboot or do anything at all with my networks. It's been at least a couple of years. Everything stubbornly keeps working. It's boring.

there is no Linksys support which is extremely frustrating and disappointing

That is understandable.

I suppose there might be a user who might see your post on an Apple site who is familiar with Linksys mesh systems and might be able help out......but at the same time I would point out that the chances of this occurring are on the very slim side.

You can certainly wait to see if someone replies, but I would keep my expectations low as far as having a Linksys technical expert help out on a support site for Apple routers.

The interesting point is that it works for 8 hrs then has perf thruput issues.

My first thought was some other “old” idevice is attaching to your Wi-Fi network at a 802.11a vs 802.11ax dropping the speed for everyone on the network to accommodate it.

You can config it to only allow AX connections, but this might access issues for your older devices or friends.

The second could be a neighbor brings up another router and its freq channel is the same as your router is set for, “without” the auto magic change channel if needed. And/or with its transmit level set to max and it’s stronger than yours and is interfering.

Hence performance issues.

Airport Extremes have a airport utility that can scan the Wi-Fi spectrum in your local area and show if others maybe conflicting with yours.

One last thing, when the speed drops, if you’re using Wi-Fi when it happens, plug into the switch directly with Ethernet to your system and try again. You might have to try direct connect to each access point with Ethernet and see if you speed changes, to identify a “component of interest”.

Good luck, and try reaching out to Cisco.com, I thought they bought linksys. Cisco has a great support team.

Isn't this really a question for Linksys Support? How would an Apple Airport router be involved here?