I'm not sure there's any way to work around the browser prompt w/o moving to Graph or using some of the older SharePoint access libraries. I did come across a really old post shown below, but it sounds like this may be what you're already doing. There seem to be quite a few posts online over the years of people trying to include credentials in an OLEDB connection string for connecting to a SharePoint list, but not many answers.
😞Cheers,
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Eric Wilson
Director, Integrations and Enablement
Blue Prism Digital Exchange
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