SRK is indeed extremely self-aware. You can tell by the fact that he opted not to use an item song or a remix in the movie. The songs of Zero are actually as good as they used to be in his movies at his peak. Have Ann Ban and Tanha Hua on repeat. In IVs Ajay Athul have remarked that SRK was very involved with the music.
Also in Baradwaj Rangan's review, he observes this, which shows how self-aware SRK is aware that his magic is perhaps no more:
"And lo, a stationary star slips out of its place and shoots across the darkness. He attempts this again at a party graced by Bollywood celebrities, but look carefully and you'll see it's not a lazy Om Shanti Om-like homage to stars on earth. From Sridevi (Army) to Alia Bhatt (Dear Zindagi), they've all been Shah Rukh Khan's co-stars. They gather around Bauua to see him perform his trick. He tries and tries. The stars above don't budge. Is it the 38-year-old Bauua (who keeps emphasising his dimples and stretching out his arms in love) who's suddenly lost his power? Or are we seeing the fifty-something Shah Rukh Khan, now in a well-acknowledged career crisis, unable to recreate the magic he once did, with the likes of Deepika Padukone and Juhi Chawla? "
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