Do I still need an H-1b visa to stay in the U.S. if I have an approved I-526?

Yes, you do, as you cannot file the I-485 until your priority date is current. You can check this in the latest State Department Visa Bulletin under EB-5 for India based on your priority date. If your priority date is current, you should file the I-485/I-765/I-131 immediately.

If you have a pending I-485, you are authorized to remain in the U.S. while it is being processed, and you would be authorized for employment once the EAD is issued. It takes approximately three to four months after filing. The I-485 processing time is approximately a year after filing.

If your adjustment has been filed and accepted and is approvable, you do not need an H-1B to remain in the U.S. EAD is taking about five to six months and the adjustment will likely take one to two years.

You will still need your H-1B to work since your EAD is just filed. Also, filing an I-485 has not yet conferred any status on you.

Following a proper filing of I-485, you no longer need to maintain nonimmigrant status. In order to work, however, you must have an approved EAD.

It is recommended that you remain a valid nonimmigrant status until you receive your conditional green card. The legal requirement is that you must be in valid nonimmigrant status at the time you file your I-485, but it is safer to stay in nonimmigrant status just in case something goes wrong with your adjustment case. You may work on your EAD for any employer, but in order to maintain your H-1B nonimmigrant status, you must only work for your H-1B petitioner/sponsor.

Unless you were issued the immigrant visa, you need to file to adjust or extend the H-1b, or both.