I personally think if the Raiders are going to make a bit splash, they would trade two first round draft picks, and a 2nd round pick (and/or TE Michael Mayer, and/or DE Tyree Wilson), to swap places with the Titans in order to take Cam Ward. This bears a risk, but it would probably be as good of roll of the dice as any IMO. It would allow the team to re-sign several players up for FA, and find another G, or DT (or both) in FA that can start.
Stafford is indeed aging, injury prone, and due a huge $49m cap hit this coming year, and $55m in 2026. When healthy, and doing well, he can certainly still throw the ball. As noted in the Eagles game he played well, and he also had a great win over Buffalo. But considering the cost, and the fact the Raiders would then not be able to re-sign several players, and have no money to sign any new FAs to bolster their trenches which is where they need help (plus other positions) it means an old Stafford would be going to a sub-average team, and expect to turn the clock back a decade.
However, it might make more sense to do that than sign some of those other guys (Wilson, Winston, Fields, Jones, etc.) as I noted who might maybe get the team 1 more win, even if the Raiders fortified the rest of their roster. I honestly don't see those guys being much better than Aiden O'Connell.
If Gronk comes out of retirement he won't be a TE for the Raiders. There's no possible way he would beat out Brock Bowers, let alone Michael Mayer. Granted, the Raiders could trade Mayer (like to move up to take Ward), but this means Gronk would mostly be a decoy.