I stand corrected, the only rears I can see on a tyre web site with the lower 104 loading (900kgs) are the Alfa version of the PZ4 and the Conti sport contact 6 which on the table shows a higher decibels. The reminder are 108 rated (1000kgs) or XL tyres.
If I can just suggest do not touch conti. As good as they are dynamically their road noise is woeful. I had the 5 for the last five years first standard and then contisilent after btchng to Volvo for 12 months about road noise. It’s not that they are just noisy the kind of noise they deliver on wet roads and rough road surface is just impossible to tune out. PZ4 on the same road sections were positively hushed in comparison. I can actually hear wind noise in this car - road noise is so mild.
I know what you mean I have never been a fan of Contis other than suspicion they last well. AR Pirelli's just feel a little like old run flats to me. I know they have low loadings but primary ride seems very good its the secondary broken roads that affect the car most and for the most part thats the tyre (40/45 profile should do better) . Dunlops other than good guarantee when they cut up have not been competitive in my experience; in 35 profile a bit understeer squidgy on the sidewall compared to the much better Goodyear Asymmetric 3. But I have not tried the RTs and not on a Stelvio. Given price difference and possibility of something more rounded I will change to Dunlops in the next 1-2k miles.