Bulk move specific files in sharepoint

Hi Duane "Open with Explorer", which is only available in Internet Explorer 11, is likely your best bet unless you need to preserve system metadata like "Created By" and "Created Date".  Copy/Pasting will update these properties.  Also I'd have to check, but "Open with Explorer" may be problematic with the number of files you have.

To keep the metadata, I would suggest getting someone with some PowerShell experience and then have yourself or the business users map the source and target for the files.  I seasoned SharePoint PowerShell developer only really needs source and target.  If you need help, my company may be able to assist.  https://www.eswcompany.com/.

Alternatively if this is going to be an ongoing exercise over time, I would recommend investing in ShareGate which is a migration utility that has been around forever, well tested, and one of the cheaper ones out there.  This will give you a visual of your entire environement, do "checks" before anything moves to see if anything will cause an error, etc.  https://en.share-gate.com/pricing.