I've been trying to finish this death wish for 4 hours. Has anyone been able to beat it, and if so, was there any strategy, or did you just get lucky?

Follow chains of pons, plan to grab tickets for the safes along the way, save the old guys getting bullied, break boxes/barrels with the witch hat, and just keep moving as fast as possible. You don't need to do the sub-objectives all at once, you can do them individually after you beat the main one, because you'll have to play them a little differently.

Best advice I can give is try and get a pathway going and learn where the high concentrations of pons are. For instance, when I start, I follow the pathway of pons forward, through the side-room with the two mafia, back onto the roadway, then detour to the right where the pipes are since there's a bunch of pons there. From there I duck down next to one of the nearby buildings, then follow the pons up the riverside up towards the central building. From there I make my way up onto the platforms attached to said building and circle around, detouring out to the construction site and the lighthouse-like structure since most have both of pons. So on and so forth.

You should have the dash hat equipped all the time, unless you need to briefly switch out for the ice or brewing hat. Make sure you have the magnet badge equipped as well - the Death Wish is nearly impossible without it. Obviously, avoid doubling back wherever possible - you should always, always, always be collecting pons. Unless you are going for the third objective (don't break any crates/barrels) blow up anything shiny with the witch's hat - they're easily your best source of pons.

The second and third objectives actually don't really require a different approach, they just require you to be even more efficient with what you're doing. I didn't find the second objective (collect no more than 200 pons) all that challenging - the first time I completed the mission, I missed it by ~10 pons, and I was able to get it no problem on the next go around (those crates are really your friend). The third - break no boxes or barrels - is much more difficult, but still eminently doable - just keep on the move and learn your path. I think it took me maybe a dozen tries total to get all three objectives.

Good luck!