First if all, Perm ma j j information bhareko ho, i140 ma ni tei tei information privide garne ho regarding ur experience and job respinsibilities. So from ur side, nothing to worry about, i140 is more related to the employer.
Next, filing separate or concurrently is all up to you. Filing concurrently will save some time and both gets processed parallely. The only drawback is if ur i140 gets rejected, ur fee for i485 is a waste as USCIS will not give you back.

If you file for premium i140, u get decision in 2 weeks and then can proceed for i485 if i140 is approved. In this case filing separate might makes sense. U can still file concurrently with premium option for i140 just to get the i140 decision in 2 weeks.

If u do not want to file premium, then filing concurrently makes sense so that both gets processed parallely u will get ur i485 decision faster after ur i140 approval. Filing separate will lose u average of 4 months of i140 processing time.