As someone with a comic that has depression, trauma and domestic abuse as major themes I would agree that a warning at the beginning of the page would be good for the parts about suicidality. If most of your comic has heavy themes then just adding discriminations in a warning at the beginning of the comic with other general warnings would be fine, or in the description. Discrimination sucks, but it's not quite as influential as depicting suicide.
My comic has insinuated that one of my MCs attempted suicide in the past, but there will be a current one in an upcoming chapter, and I plan on putting up a disclaimer just for the chapter in spite of already having CWs in my description. (and as a pop-up on my main site) Visually depicting stuff like that is really serious business, even when you're doing your best to be respectful it can still influence and hurt people. I'm not saying don't do it, because I would be a hypocrite, but I would say be very careful.
Here is a really informative video on the subject if you want to go into it with a deeper understanding.