i might not promise that you'd get a good college for BE/BTech with this rank and if you do what branch you'd get as there is even a huge rush in the field. but with 21K rank, you might get a good college in BArch/BPlanning.
look for colleges from this link as per your category and branch choice
https://engineering.careers360.com/articles/jee-main-cutoff-for-b-arch-b-planning
all the best
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