Pages is not a Word clone, and there may be content in some Word documents that simply fails the Pages translation process when attempting to open them (including document age). See Pages User Guide for Mac - Apple Support
I would recommend that you keep the free LibreOffice Suite installed, as sometimes, I have encountered Word documents that neither Pages nor MS Word could open. I open these in LibreOffice Writer and then resave them as Word .docx again, and usually, that is sufficient to get them opened in Pages or Word again.
You can associate the default opening application for Word documents as Pages, so that when you double-click on the Word document, Pages attempts to open (and translate) them. Click once on any Word document in the Finder. Press option+cmd+i to expose a Get Info panel middle-screen. On that panel is an Open with section. Change that application to Pages, and then click through the Change All… button. Then close that Get Info panel. The next time you double-click a Word document in the Finder, Pages will attempt to open it.
Unless you are required to exchange Word document content in a corporate settting, or someone (e.g. publisher) that may require a Word document from MS Office, then you can probably get by with Pages. Otherwise, I would not recommend Pages for corporate environments and you should consider either a subscription, or single-purchase of Microsoft Office for Monterey, or look into the free trial of SoftMaker's Office for Mac solution which unlike Microsoft does not follow Apple's three-year operating system support cycle.