Split Not Working With With Dual Browsers

When I try to open two browsers on the split screen it doesn't work and says that the app is not available fore split screen. I tried to use Arc and Safari side-by-side but when I clicked on "Tile window to the left of the screen" and then chose the other window from Safari, it showed that Safari is not available for split screen. Is this how it is? Any suggestions? Thanks in advance :)