The update may have introduced new and unasked for wifi problems, but on an ethernet connection you'd be unlikely to see any problem.
You've tried a different cable? I had this problem recently on my 200 Mbps connection, and it was a flakey cable, which had worked Ok for years, but now was causing the hub to flick between 100 Mbps and 1 Gbps protocols. Obviously the 1 Gbps is overkill on our 200 Mbps, but the practical impact of the cable issue was intermittent halving of speed.
Almost any borrowed cable will do for testing purposes, since it's two decades since non-gigabit ethernet cable was widely available, but if buying new I'd opt for Cat 6a or higher.
@lordmelch a speed of around 85 Mb/s is highly suggestive of something has negotiated the port speed to 100 Mb/s. As you have tried multiple devices and cables that would suggest the hub ports themselves are the culprit. Now there have been reports of hubs spontaneously having port issues or even not working at all, which may well be related to a firmware update.
I take it you have tried different sockets on the back of the hub as well as a simple reboot of it with no improvement, the next step is a full factory reset of the hub. To do this, stick a paper clip or similar into the reset button on the back of the hub and leave it depressed (you’ll feel a faint click as it presses the button) for a good minute. The hub should reboot and come back up as it was when you first got it, ie the WiFi SSID and password will be back to what it says on the sticker as will the login password for the hub so you’ll need to log back into it and setup any changes you may have made again.
Incidentally before you do this, make sure that the sticker is there and is readable otherwise you’ll be a bit stuck when it resets!