What should I do when my B-2 expires with pending I-130 and EB-5 I-485s?

It would be inconsistent to claim to be a visitor with an I-130/I-485 pending, assuming you have been receipted.

A B-2 extension would not be approved with the I-130/I-485 pending. The pending status is a period of stay authorized by the Attorney General so you do not need to do anything.

If you filed a timely I-130/I-485 based on marriage to a US citizen, you will be in an authorized period of stay while your case is pending when your underlying B-2 status expires in March 2023. You should not travel outside the US until you receive an advance parole document or a combo card (employment authorization with advance parole document endorsement). You may choose to file a B-2 extension but it is not necessary and may very likely not be approved since you have an immigrant intent by filing I-130/I-485.

That means you entered in Sept 2022. If you file for a B-2 extension you will be committing visa fraud as your intent is obviously not to visit for a little longer. You remain in lawful status because of the 485 filing. If you filed your case too soon with no change in circumstances, you could find yourself in the same predicament. Hopefully you obtained sound counsel in your application. If not, you should do so immediately.

No, you do not need to extend your B1/B2 status.

If your Form I-485 is pending you do not need to extend your B-2 visa status because you are considered to be legally in the US. Nevertheless, if your I-485 application is denied, you will need to leave the US or file an appeal or in some cases a new I-485 form.