Okay - so a few things to note:

1. Ignore campaign. Stick to farming Brutal 12-3 or 12-6. Come back to campaign much later, when you can effortlessly 3-star everything.
2. Get a basic CB team going, even if only just to get Brutal chests
3. Get Dragon 20 on farm

So, to that end, let's start with the last one. For your Dragon 20 team you will use:

• Artak (waveclear + bosskiller)
• Stag Knight (debuffs)
• Toragi (provoke) - put A2 on opener + disabled for wave1
• Drath (heal + revive)
• Khatun (speedbuff)

You'll need all except Khatun to be at 60. Khatun you can bring to 50 for now, but you'll probably end up wanting her at 60 too.

Unfortunately Artak really need books to shine, and you probably don't have a huge number to spare. Get him booked ASAP.

Kram gave you great advice.  This is a grind game.  You work hard, make slow incremental progress.  Then it gets better or worse.  :)

I took a break also.  The game is more fun the 2nd time aournd.  Welcome back.  

Thanks a lot for the great advice!

Artak and Wu Kong  need to get to  lvl 60 imo

Does he need to farm 12-3, 12-6 and Dragon20 for better gear before he is ready to gear up Artak and Monkey?  They are both great champs but they need books, masteries and gear.  

Gotta go thru it in stages and I agree getting them to 60 is the best 1st step.  Once they're 6* you can use them to help grind all those other areas though of course they won't ve at their max potential.

Awesome and welcome back!

You've got some great champs you can rank up in Artak, Wukong, Stag Knight and Nia! That's where I'd start personally, getting those champs to 60 through food farming, then moving towards progression in Dragon to get gear to work on CB champs.