485-140 is one to one relationship

Since your eb3 140 is approved, you can use eb3' PD for your eb2;

it's the safest to invoke ac21 after your eb2 140 approval.

If you want to take risk, and you expect your eb2 140 will be approved without RFE, or your current employer will response 140 RFE (if there is one) well, then you can switch your job.

Usually, if there is a 140 RFE, and your previous HR simply reply: "this is employee is not working for us anymore", then 140 would be denied. 485 will be denied right after 140 denial.