As you mention Amex points it’s worth bearing in mind before you convert any of those to airline miles have a look at what redemption options are like. Many people (pre pandemic) happily praise Virgin, but outside of New York their redemptions have become very scarce.

AirbusA350 I was intrigued by the bar the new AY seat remark. I think we’d all need to reserve judgement until we’ve tried it, but it looks awful to me and I fear the lack of proper back support will condemn it to useless for many of us, albeit trying it will be the real test. I’d hope to do that on one of the LHR-HEL rotations, don’t fancy longer than needed on something so radically different.