These are exclusively public, user supported communities. No Apple employees participate here and only proper feedback links get to the the product development teams. Continuing to post about issues with Preview in Tahoe 26.0.1 is just noise as we fellow users cannot fix it, and Apple won't see it.
Even a change in the tools that the originator of the PDF uses, could impact how well Preview can select and annotate text passages. PDF document internals are a quagmire. Not only is Apple's Preview incapable of handling all PDF documents, the PDFKit/CoreGraphics development teams sometimes introduce bugs in it. I keep a current version of Adobe Acrobat Reader installed on the occasion when Preview has issues.
Neither Preview, nor Acrobat Reader are PDF Editors. One does not need PDF editing features for PDF annotation. When PDF editing is necessary, there are single-purchase, lower cost PDF Editors (e.g. Code Industry's Master PDF Editor) available for those that are sensitive to subscriptions. Recently, if not presently, stacksocial dot com was offering a Microsoft Office 2021 Home and Student plus a 3-year subscription to Adobe Acrobat (classic) for 89USD. That same three-year subscription from Adobe would run 324USD.