sorry for late response, i dont check replit that often.
you can go to https://repl.it/@p0lys0ulz/NOX and try it out.
learning flex and bison is not hard, it took me only one week, with around 3-4 hours a day.
you can find good resources online, some are textbooks from courses in some universities ( those are the best ).
send me an email if you want any help !