If you are doing a comic I would suggest posting on canvas webtoons, tapas, mangaplus, and other sites that will increase your fan base. But you have to decide what is your main goal?
For example, do you want a chance to grow big or go home? I recommend webtoons for that. Canvas section can easily get you a fan base since webtoons app has a huge fan base compared to other apps plus canvas can really grow if it has good art or great comedy.
The downside of webtoons. Even though you can grow a lot I have noticed fans prefer art over a good story on webtoons. Many new canvas win the opportunity to get serialized but their story telling is super lacking full of plot holes (even awful grammar) among other things but great art.
Now I do notice anyone with an original concept comedy wise tend to be a big hit over there even if their art isn't amazing like the best webtoon over there. That's a plus for anyone with a concept such as stickman isekai. Another plus is that newly updated canvas do get seen a lot so winning a fan base isn't as hard as other webpages.
Now if your goal is just to increase your fan base post everywhere you can.
THERE ARE NO RISKS posting on multiple websites EXCEPT the obvious copycats here and there. But usually copycats are not super common unless you make a huge fan base.
I guess you could also forget updating one platform if you consider that a risk?