I think SRK did his best movies in the 2000’s. The 1990s was a phase of the becoming of SRK with lots of hits and misses. 2010s onwards he either didn't try at all or tried too hard with mediocre content.
In the 90s he did Very Good films- Baazigar, Darr, Kabhi Haan Kabhi Naa, DDLJ.
Some popular films which were great then but may not have aged that well today- Kuch Kuch Hota hai, Dil to Pagal hai, Karan Arjun, Pardes, Deewana.
Then he had films which were feel good films not great but good enough to put smile on your face- Raju Ban gaya gentleman, Chamatkar, Yes Boss
And films which remained underrated and didn't receive the appreciation it deserved- Anjaam, Dil Se, Chahhat, Badshah, Maya Memsaab
And then his bad and atrocious films- Dil Aashna hai (bad), King Uncle (loved it as a child but not as an adult plus SRK was barely there), Guddu (Trash), Zamana Deewana (utter trash), O Darling ye hai India (utterly bad film which tried to act way too smart), Trimurti (Big budget trash), Ram Jaane (not bad as a film but SRK was so over the top in the film), English Babu desi mem (very bad), Koyla (not a bad film but too excessive in violence, not an easy watch), Duplicate (could have been fun but a mess). Not including his cameos in Army (which was also bad) and Dushman Duniya ka (very very bad)
In the 2000s he had a much better filmography. His great to very good films will include- Swades, Devdas, Kal Ho na Ho, Veer Zaara, Chak De India
His Good to decent films without the same recall value include- Kabhi Khushi kabhi Gam, Mohabbatein, Main Hun Na, Kabhi Alvida Na Kehna, Don (good film would have received much more love without the comparison with the original), Rab Ne Bana Di Jodi, Chalte Chalte, Om Shanti Om (a really entertaining film except the plot heavily copied from Madhumati especially the climax)
His underrated films will include- Phir bhi Dil hai Hindustani (more relevant in today's condition of journalism), Ashoka and Paheli (also his cameos in Hey Raam, Saathiya and Luck by Chance)
His not so good, bad and atrocious films will include- Josh (the film was quite decent just SRK doesn't suit in gunda type roles), One 2 ka 4 (could have been fun but a mess), Hum Tumhare hai Sanam (SRK was very good, but the film would have been better had it not been delayed for 6 years), Ye Lamhe Judai Ke (a cash grab scheme to take advantage of SRK's stardom)
In 2010s SRK had a decline in his career. In this phase he only had one great to very good film- My Name is Khan.
His Good to decent films will include- Don 2, Raees, Dear Zindagi (I personally liked it)
Most of his films in 2010s were mediocre not bad but also not good- Jab Tak hai Jaan, Chennai Express, Ra.One (graphics were great screenplay was pathetic), Fan (underrated, went overboard in the second half otherwise SRK's best performance in years)
And the bad to utter trash- Happy New Year (what nonsense was that), Dilwale (the same question repeated), Zero (confused film ended up nowhere while trying to be everything), Jab Harry Met Sejal (except great music nothing worked for the film)
In 2020s he had 3 releases and while none of them was great, Jawan was still the better one followed by Pathaan and Dunki. I don't except King to be anything but fan service movie.
So I would prefer the early 2000s SRK