1. I've read plenty of manga, so I'm more familiar with them and how I feel is definitely dependent on the writing and art style. Bakuman (from the creators of Death Note)? Love it for the art style and story. I also love how it shows you how the mangaka industry works to a degree, from the standpoint of close to 2 decades ago now at least. Currently don't have a manga series in my collection I don't like, so can't say anything about one I dislike currently.

2. I have not read any manwha besides a series I have the first 2 books of called Zero/Six. I don't really care for the whole webtoons thing since I'd rather collect a physical copy of a series for something of similar style to a manga.

Side note: I have reservations about continuing to read Zero/Six considering I just looked at volume 1 to confirm something and I was right when thinking I remembered Hitler being in the book. He's literally the main characters German teacher and within the first page we see him he's literally called Hitler (looks exactly like him too) and does a Nazi salute after beating a students ass with a wooden stick(?). I get the book was originally published in the 90s and translated in the mid-2000s, but that's definitely a pretty big red flag for me on an otherwise pretty good series.

3. Manhua is the one I'd say I definitely have the absolute least experience with. Closest I have is finding some translated Fei Ren Zai 4 panel manhua online. Props to the creators of that manhua and the donghua because I like them for some of the comedy and random short skits. Not much else to say.