'Connecting an external debugger for browser extension development

I'm trying to figure out how to properly attach an external debugger from, say WebStorm or vs-code to debug a browser extension.

How my ideal workflow would look like:
I launch an extension in dev-mode with https://github.com/mozilla/web-ext and then can attach debugger to that browser instance, see break-points/etc.

What I've tried

Configure https://www.jetbrains.com/help/webstorm/configuring-javascript-debugger.html specifying a URL on which my extension operates.
Add a break-point to a content-script
After browser is started by debug process - load my extension from disk & reload the page

Expected: debugger stops at a break point
Actual: page loads without interruption (or sometimes debugger stops at a random code not from my extension 😅 )

I've also tried setting the breakpoint for a background script, which didn't seem to have any effect either.

Misc

For content-script WebStorm seems to indicate that break-points are not in a valid state
Background script breakpoint is, not that it helps
Code is bundled with Parcel with source-maps enabled
Browser is Chrome 99.0.4844.51 (FF debugging does not seem to be supported)
System: macOS 12.2