H1B transfer pending taking time

My new employer filed for H1b transfer and received an RFE for paystubs. This was duly provided.

The case status still shows request of evidence received and they are processing. It’s been 10 days.

What is the normal time for adjudication these days for a transfer? Can they ask for more evidence or should I just hang tight?

It can be long, unless it is filed in premium. You can check USCIS website: https://egov.uscis.gov/processing-times/ to get an idea. It can be few weeks at least.