You are attempting to implement access to the Google Web store with the path, /detail/xxxxxxxxxxxxxxxxxx, "xxxxxxxxxxxxxxxxxx" being a dynamically, changing, path to specific Google Chrome extensions within the same website. It's confirmed that you are able to access Google Web store, and can control access to the primary page, except that you aren't able to control access to the individual extension, through policy, on the Proxy.
While access to Google Web store can be controlled via policy, controlling access to the individual contents (Chrome extensions) /detail/xxxxxxxxxxxxxxxxxx can't be done via policy in the Proxy, specifically because /xxxxxxxxxxxxxxxxxx changes with every access from different users.
Howbeit, you would be able to control/manage the required access to the individual Chrome extensions using the Microsoft Group Policy, or by implementing a Chrome-specific solution. Please see the following non-Broadcom resources, and may provide some guidance into how you may implement controlled access to the Google Chrome extensions.
https://docs-previous.pega.com/pega-rpa/using-microsoft-group-policy-control-access-chrome-policies
Additional Doc.: https://learn.microsoft.com/en-us/deployedge/microsoft-edge-manage-extensions-policies; https://support.google.com/chrome/a/answer/7532015?hl=en
Please engage your Microsoft Tech. Support, for GPO-specific guidance.