Vibration has the same effect on me. Waking up in general is a not very nice experience most of the time. Weighted blanket helped a little but it's still kind of stressful.

There’s a lot of alarm sound choices on iOS that aim to be a bit more gradual rather than something like a fire alarm. Mine sounds a bit like some distant music that gradually gets closer.

I have a very slow and long chill song, set to increase volume one step every 5-10 seconds. It takes a good two minutes of playing to max the volume (the song lasts like 7min). I'm almost always awake before it reaches max, and never with a jump scare.