They make (made?) clips that would hold the dash in to resolve your issue. I think they were called Dash Saver or something like that. LMCTruck used to sell them, as did Classic Parts.
Some L-brackets painted black would probably suffice. You could bend them to match the dash curve.
Your bezel issue probably requires a new dash. I found one for $100 at a salvage yard here to use on another truck. It’***** or miss now. Try car-part.com for a decent salvage yard search engine.