The Delta 561 line of faucets are nice, and the price can vary considerably among models that are only different based on the flow efficiency regulator. The faucet I wanted in the flow rate I needed was nearly 3x the price of a faucet that only varied by model number and flow rate. I called Delta to verify, and did the following:
I swapped out a commercial line Delta 561-HGM-DST 0.5 GPM regulator for a residential 1.2 GPM regulator. The 1.2 GPM version was over $200 at the time I bought this, and the commercial version was under $80.
0:00 What is a flow regulator?
0:20 Flow rate regulator options
0:38 Where is the regulator?
0:56 Removing the regulator
1:31 Installing new regulator
This faucet is somewhat similar in design, but different to the original that is currently showing out of stock. You can see different flow rate versions at the link.
Delta 581LF-HGM-PP
amzn.to/2ZYBbxu
The faucets below are the originally reviewed faucets, but all are showing out of stock as of the time I'm typing this. Maybe they'll come back in stock, or maybe they are discontinued.
Delta Faucet 561-HGM-DST (0.5 GPM)
amzn.to/3EJ0Xoc (cheap version)
Delta Faucet 561-GPM-DST (1.0 GPM)
amzn.to/3GOrDWq
Delta Faucet 561-MPU-DST (1.5 GPM)
amzn.to/3GLYvPH
Delta 1.2 GPM regulator:
www.deltafaucet.com/parts/product/RP75432-1.2.html
(Delta sells various flow rate options under the Delta RP75432 model number). If you call Customer Service, they are pretty helpful and actually pick up the phone.