There never was an option to upload a docx template for Statements, @Woodpecker UK Ltd - only Invoices & Estimates.

(that was the initial bugbear of this thread - QBO Statements are woeful)

However, as per my post a couple of months ago (up there somewhere ↑), if you have previously uploaded a docx invoice/estimate template you should still have the option to upload new ones.

I haven't gone through it but I certainly still have the Settings>Custom Form Styles>New Style>Import Style gives option of Invoice or Estimate.