Love & Life & Lie (2017)

FL got swapped from birth
one ends up in a rich family, other in poor
antagonist tries to prevent FL from finding happiness
foster mother mistreats FL after she finds her biological daughter
biological mother of FL also mistreats her daughter
female leads fight for the same man
step-brothers compete for their dad's inheritance

Girl! I promise you this is the exact drama. Hmm... it has the evil mother, evil girlfriend trying tear their faith apart. You better get that drama your currently watching out of your anal 'cause this is lit as fuck my weebs.

Similar concept of interchange of identities of a poor and a rich girl.

They both have girls switched at birth. One was raised in a wealthy family well the other was raised in a poor family.

These two dramas are nearly identical at times, but I feel that Kaew Lorm Petch is the better version, although it's tone darker and has a much more satisfying ending.