There’s a way of linking such that clicking a link in obsidian goes to a particular annotation in Zotero - and I’m sure there’s a way of going to a particular page. I originally used Zotlit and a customised template… then tried another plugin… and have only just come to Better Notes (for the bidirectional sync which is wonderful!). I also use the Actions & Tags plugin which supports (amongst other wonderful things) scripts that enable creating link-to-pdf-in-Zotero creation/copy. I’ve only just started using Better Notes in the past week so am still in the process of developing a robust workflow for me - but will have a look next time I get a chance to check the functionality and find out what the link to open to a particular place in the pdf in Zotero looks like.
I’m sure the Actions & Tags Zotero plugin can do what you’re asking - though Better Notes may be able to be set up to do it automatically 