I've been happily using Outlook on my desktop for years and managing my calendar locally. I recently purchased Microsoft 365 Family, primarily to get the Office suite of local apps on all my home computers and maintain them at current versions. I installed the apps locally. Now when I double-click a downloaded .ics file it will only open in "Calendar", which appears to be my Hotmail calendar. I have a Hotmail account, but it is definitely not my primary email -my primary email is a POP account in a custom domain that I have managed myself since 1989, and I have no desire to change it. I can't select my local Outlook app as the default program for .ics files. This is a major inconvenience, as I sync my local calendar to my Google calendar with Sync2.
How can I set Outlook as my default calendar program in Windows 10 with Microsoft 365 installed?