Visual Regression für automatische Updates

I’m currently trying to improve my maintenance workflow for 20 WordPress sites, and I keep running into the same issue:

Good, customizable visual regression testing around automatic updates seems extremely rare.

Specifically, neither ManageWP nor UmbrellaWP offers:

* defining exact custom subpages/URLs to test (e.g., landing pages, checkouts, special templates)

* properly testing mobile views

So I’m wondering: Which tools (SaaS or MainWP plugins) offer the best visual regression testing for WordPress updates, especially with:

* custom URL lists

* mobile views

* selectable browser/viewport