I second @Cronaj, for most artists fully pencilling, inking, coloring, and lettering a 20-40 frame chapter every week is a full time job.
For reference, since you may not realize just how time-consuming comic art can be... A 20-40 panel chapter is the equivalent of about 4-8 comic book pages. Industry standard for comic book art is roughly pencilling one page per day, inking about two pages per day, and coloring and lettering about five pages a day, and that is as their full time job working eight hours a day. If you want one person to do all of that alone, it will take them between 7-14 days to do a single chapter, working eight hours a day, every single day. And that is for a professional or semi-professional artist who can work at that speed. Anyone willing to work for free will not be at "industry standard professional" levels of speed.
If you want an artist to work for you for free, you will need to honestly reevaluate your expectations.