I've been experiencing severe problems with WiFi connectivity since this update. Normally, I use my phone as an FTP server and access it from my desktop via FileZilla, but since last week even establishing a connection has been difficult. I get this in FileZilla: Connection attempt failed with "ECONNREFUSED - Connection refused by server".
I need disconnect and reconnect my desktop computer to the WiFi router for it to eventually connect to my Pixel's FTP server.
Also, if I try to run a speed test on my Pixel (using WiFi only, SIM disabled), I get a socket error, whereas it runs just fine on my computer on the same WiFI network.

Signal and Telegram are barely usable when on WiFi (messages won't send), but if I just use my SIM instead, they work as they should.