Computer Configuration > Administrative Templates > Microsoft Edge > Sleeping tabs settings
Both
HKLM\Software\Policies\Microsoft\Edge
Define a list of sites, based on URL patterns, that are not allowed to be put to sleep by sleeping tabs. Sites in this list are also excluded from other performance optimizations like efficiency mode and tab discard. If the policy 'SleepingTabsEnabled' (Configure sleeping tabs) is disabled, this list is not used and no sites will be put to sleep automatically. If you don't configure this policy, all sites will be eligible to be put to sleep unless the user's personal configuration blocks them. Example value: https://www.contoso.com [*.]contoso.edu