How can I salvage this 25 year old deck?

Hello,
I have a roughly 25 year old deck (~600 sq ft) that the previous homeowners "restored" with Behr Deck Over before they put the house on the market. Within the first year we could see a lot of bubbling and chipping all over the deck and now after three years it's gotten bad enough that I'm finally attempting to fix it.

So far I've tried using a chemical stripper in a small location, but it was spotty at best, and left a lot of mess after scraping & pressure washing.

Next, I rented a floor sander (non-drum version) and that seemed to be a lot less messy, but not nearly as effective as I'd hoped. After several passes and a bunch of 20-30 grit sanding sheets, this is the result.

So my questions are:
Is it worth using one of the deck restore products with all of the splintering I have?

If it is worth doing, do I need to remove more of the stain that's already down?

Will the peeling stain between deck boards cause issues for any restore product I choose?

How can I save this deck?

Thank you for the help!