Hi, I am Nigel, Independent Advisor here to work with you on this issue.
Sorry, I seem to be answering this question more than any other, so your not alone!!
When initially Edge Chromium was release you were able to uninstall back to the old Edge. This functionality is unfortunately not available now due to vulnerabilities in the old version which are not updated. It will be included automatically as part of patching as 'OLD' Edge has unpatched vulnerbilities.
You can set an alternative browser in Windows 10 using the following instructions.
Change your default browser in Windows 10
Select the Start button, and then type Default apps.
In the search results, select Default apps.
Under Web browser, select the browser currently listed, and then select Microsoft Edge or another browser.
I hope this answers your query, apologies if it is not the answer you wanted.
Feel free to ask back any questions and let me know how it goes.
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