Hey PC Gamer I believe I can help you out on your request.
I've nav'd over 100 maps in total and I actually achieved some unachievable Nav's which sounds weird when you talk about something which players quickly "nav_generate" in general.
I actually Nav most of the maps on all the servers I run since my servers really rely on Bots at first when player numbers are low.
A good Nav does wonders for how playable a map is with bots and gives a better quality improvement gameplay wise compared getting the bots plugins to improve them in general, hence why I have some maps where I spend incredible long hours in making custom ones (5 hours in general if you talk about a Stock map)
Maybe I can provide some of the maps you need' Got the same user name on Steam.