Blocking weak passwords in the browser?

I'm a fractional CTO, not an MSP, but I'm often involved in the IT and security setup for my clients. I'd love to hear all of your thoughts on a challenge I discussed with a client a little while ago:

They raised the concern of password security, and specifically how they had a hard time getting their non-technical staff to use password managers and strong passwords.
That made me wonder if it was possible to stop users from setting weak passwords anywhere by hard-blocking them browser-side (running locally, nothing sent across the internet). I couldn't find an off-the-shelf solution and put together a Chrome extension as a proof of concept. Unfortunately, my client had more urgent matters to deal with so we didn't try it out in practice.

From your point of view, do you think something like that would be relevant for your clients?

Right now, all I have is a basic proof of concept and I'm wondering if it's worth investing more time in to create something usable for people other than myself. I'd greatly appreciate any thoughts and suggestions!