SkullX quits by either pressing the red cross or cmd+W
Neither of those quits Orion. Instead, by using those you are telling Orion to discard the tabs in that window.
SkullX Please for god sake remove this or at least give the option to reopen the previous window which was in use having several open tabs like chrome
⌘+Q does precisely that, as long as you have Orion opens with: All [non-private] windows from last session set in Orion settings -> General.

This is how Safari does it as well, and to my knowledge that is how Apple intends it to be done. If some browser is not following that behavior, they are deviating from the norm.