he seems intent on shoehorning Ahsoka into every project he works on.
She is not in every project he works on. She was not in Resistance. Also, I wouldn’t say being a supporting character in just a few episodes of Rebels would constitute shoehorning. Her popularity makes it seem like she’s everywhere because she is frequently mentioned, but shes mostly just in The Clone Wars.
making it so that she can never die causes her to overstay her welcome somewhat.
I’m sure she can die, but It would be hard for a character as popular as you’ve mentioned Ahsoka is to overstay her welcome.