Interesting point.
The Tory party is generally much better on the diversity front (See Boris's cabinet, two female prime ministers, and I think the first to have LGBTQ members who were "out" of their own accord).
So I think in this sense the path to senior cabinet positions for those from diverse backgrounds is well trodden.
What hasn't happened before is having someone who is a different race or sexual orientation, in the PM position.
So I think, in an unconscious bias kind of way, it is easier to imagine Truss as PM, it is harder to imagine Sunak.
I don't like either (have never voted Tory) but if I had to choose the least worst option I would go for Sunak.
But being British Asian myself I have reservations of Sunak coming to power as I feel, rightly or wrongly, that this could impact the British Asian community adversely. It's like in a weird way he represents us all (even though he doesn't).
When he inevitably does something unfavourable, people will bring race into it, and in turn I sort of feel it would tarnish us.
Would Boris have been able to get away with all the terrible things he's done if he was Asian? To be honest I don't think he'd have even become PM.
Anyway that's my two pennies worth - better save the rest for the cost of living crisis.