I am having an issue very similar to this one. However, all the settings noted in the accepted answer are turned on for me. I have used find my phone in the past (though not for a while). I don't know how or when it changed but I haven't had this problem before.
I am able to see my phone on my account's devices, but the options there are not very useful:
As per here I also installed the Find My Device app on the phone. I can see my phone there, but I don't understand how that's useful (I could only find my phone from my phone if I have my phone already). The phone still doesn't show up on the web. Any help/ideas are appreciated.