screen resolution 1280 x 1024 not available as display choice imac OS Catalina

I need screen resolution of 1280 x 1024 for a certain function on an important web site but when I try to adjust it (Preferences-Display-Scaled), I only have 4 choices, and none are 1280 x 1024. Using MacBook Pro, 13" 2019, running Catalina v 10.15.3.

I tried all of the scaled choices but none of them produced the results I need on this web site.

Any suggestions?

Thanks