Where your at right now, you basically have no travel left in the suspension. If you cut the bump stops, you wont gain any ' real ' travel and only allow the rear leafs to sag more.
A ' notch ' setup does NOT weaken the frame at all. In most instances, it makes it stronger.
Notch kits are usually a ' plate '. They bolt ( I weld them on myself ) to the frame after you cut a small section out so you have more travel room for your axle.
If you take a good look, the plate itself is 2 or more pieces that have a STRONG weld holding it together. The construction in itself is stronger then the regular frame rail section you would remove to put the ' notch ' in.
If done properly, theres no worries to be had at all.
One of the mods here ( ScottyG ) had his truck SLAMMED, then he went and lifted it and left the notch on his frame in the rear. He went offroading with it and had NO issues at all with his frame.
Your running into an area a lot of the ' lifted ' people are addicted to. Fashion over FUNCTION. Going for a ' look ' when it hinders operation of some other aspect of the vehical.