You can use a mild stripper on the poly, but that could damage the staining and the wood. So, I would select and elect to do sanding. The poly is not that thick and it will sand very nicely. Then you will need to restain the wood.
Now, I would still go back with polyurethane but NOT oil based, which always yellows, go with the water based poly and use multiple coats, Each coat dries in about two hours.