macOS Sequoia network issues
Like many others, Sequoia started behaving very sluggish from the very beginning. The computer itself was slow, but I also had trouble accessing the company's Microsoft 365 environment. I couldn't access SharePoint, OneDrive repeatedly asked me to log in, DNS resolution frequently didn't work, Teams refused to allow me to join meetings, the browser versions of Office, Excel etc didn't work, etc.
First thing was to uninstall the VPN software I sometimes have to use to connect to the office network from home. I'll wait for the vendor to release an update.
While at the office, my MacBook Pro is connected to both WiFi and cabled Ethernet. Once I unplugged the cable, things started behaving better - that's clearly a bug, and it has always worked just fine in older versions of macOS.
Setting Private Wi-Fi address to "fixed" helped with the frequent network disconnects. I've now set it to "off" (because I rarely use public Wi-Fi networks).
Things are now mostly back to normal. I hope this helps others struggling with similar issues.
MacBook Pro 15″, macOS 15.0