Hi @Namraj_Jaishi ,
It appears that you are losing 50% of your data from failed merges, and more again as many are detected as chimeras.
What amplicon marker gene and region are you targeting? What length are you expecting after merging?
You'll likely have to play with the truncation parameters to obtain more merges, and also investigate the use of the --p-min-fold-parent-over-abundance to mitigate false positive chimera detection. You can also, optionally pool the data too. These are outlined here.