+1 here, or +a team of 15 people.

Saving your password for 1Password in 1Password seems like a terrible idea. Please find a way ASAP to block certain websites.

The only close to workaround I've found as an administrator is this:

In a vault that is shared with the entire organization create a log in with these settings:

Login Title: x DO NOT save your log in for this site.
username: Login Blocker (ask IT Admin)
password: x

(Don't put the term "1Password" or "Password" in the Login Title, this keep it from turning up in day to day searches of 1P. The password is literally one character. So that if it ever did get filled it would be obvious that the password is only one character.)

website: https://1password.com
website: https://my.1password.com/

then do the filters for "Never fill on this website" for both.

All this creates a pop up reminder team members to not attempt saving their PW to 1Password. This login is buried in a vault that no one would search out. But 1. admins can't lock editing of a Login so anyone could edit it and 2. I'm not sure how the conflict would work if they attempted to create a new password for this same site from within the app. There would be two instances of the website in the 1Password database, one blocked one not. For that matter a team member could still save their PW in 1Password they just can't fill it on a site.

.... y'all just fix this please.

+1 here + a team of 3.

Please implement this, as @YvesRausch wrote:
"It is quiet simple: Add in context menu > Don't use 1Password on this site, add to blacklist, all be happy."