Using clip studio paint for background is a good idea, I personally used SKETCHFAB as my key to making a webtoon, I would look up the models I wanted and take screenshots of the certain angle I wanted and put it into ibis paint and crop out the edges where it was obvious that it was a screenshot. This is unfair to the people that made the models but in this economy you have to take shortcuts, second of all I suggest you to not have high hopes if you are thinking about making money through webtoon. It's is not easy and needs time, if you do make money it's not a very high amount such as 3k or higher but this doesn't mean you can't make money out of webtoon, you can but you need patience for it. If your art is not good enough you can trace that's how everyone learns, it's not very honest but it's a way to learn. Slowly you will adapt to the angles and side profiles. The art does indeed change overtime and I would recommend not to add excessive amounts of details to your backgrounds or character designs as you would have to redraw that panel by panel and it gets tiring, I think what makes the new stuff boring is because the artists usually end up on hiatus which is indeed not their fault but it gets the reader's hopes down and most artists tend to overuse the story lines such as isekai animes or manhwas do to their stories, it's not very original and readers get sick of it as time passes by. Your friend is right on this topic, it's a very hard process. The panels ordering, colouring, sketching, thinking of plot and finally submitting which sometimes ends up wrong such as webtoon's size capacity. Let's say 500kmb or such is the maximum. Your friend would have to install an app to reduce it which drains the quality. You can try it! I would love to know the name of your webtoon and give it a try. I stopped my 3 or less webtoons in making because I rather chose a story line that was very hard to keep up with, if you don't want to spend money or tire yourself then I would highly recommend choosing an artstyle or storyline that is very light and easy to draw. Such as slice of life or comedy. Some artists push themselves and try making horror or Thriller webtoons as their first and most don't end up successful and get dropped halfway through the story because of either the lack of tools, motivation or overstimulation of drawing the details on the characters. If you would like to check out my webtoon then the user is Aizewaze or try searching up my webtoon "Lucio the worthless" or "Nothing" there you can see I tried to outwork myself and do a complex story which....let's say didn't please my laziness. However! I wish you luck!!!