Okay, but is it not what you wished for, "a similar tool for the modern era"?
edit: I see I simul-posted with u/modeless, but I can't remove it now that there's a (duplicate) reply. Maybe mods can remove or at least collapse mine (their ID is one lower so they were first)
WinDbg is just a debugger: it does not assemble or disassemble. It can't patch running programs in memory. Moreover, I don't consider Windows to be part of the modern era, as I haven't used a Windows machine for 20 years.
So, no, WinDbg has nothing to do with debug.com.