Update: no one will likely see this, but I'm the OP and workaround turned out to be simple and not involve burner phones. I deleted my linkedin cookies, waited

Update: no one will likely see this, but I'm the OP and workaround turned out to be simple and not involve burner phones. I deleted my linkedin cookies, waited a few days, changed my IP address, and was able to log in without handing over my phone number. They lock this nasty screen in using cookies or possibly your IP address. I'm guessing it's to harass VPN users.