My experiences when I've flown in QFi Y as SG have been remarkably consistent. I don't expect anything (and I don't ask anything).
In my experience the CSM cabin walkthrough greeting + "let me know if there's anything I can do" is only for WP and has never included me or other SGs. Rarely I might get a brief acknowledgment while seated next to a WP but never "let me know if". And otherwise it causes me to grin when CSMs talk past you to an adjacent WP as if you were invisible and then move on
Some notable exceptions/experiences. Flying into BNE once, the plane must have been abnormally devoid of status pax, which was implied by the number of empty seats around the front of Y. I hadn't observed any CSM walkthrough but then late in the piece the CSM gave me the full welcome as if I was WP, leading me to think there were no WPs in Y.
Another time, the CSM had a brief conversation with the WP next to me but then talked to me, which was so shocking that I was literally speechless for a few moments lol. She gave the WP noise-cancelling headphones and also gave me a pair, which was appreciated.
One time the CSM did a pre-landing walkthrough, which included me for some reason. Just a brief goodbye and "hope you were able to get some rest" on the overnight flight, but when she heard I was unwell she (unasked) got me hot water with honey and lemon, which was very nice. (But maybe I should have thought to request panadol ...)
Lastly, best of all, was the
offer I couldn't refuse. That wasn't the CSM but I suspect if I had been lower than SG I may not have gotten the offer.
But overall in my experience, SG in QFi Y cabin = may as well be PS!
Edit - was a little disappointing to get precisely nothing (not even an acknowledgment) when flying Y long-haul as SG on one birthday. Even Scoot acknowledged a pax birthday on one flight I took!