I think it's important to emphasise that having to live with the continuous fear of not being accepted as an equal part of society or worse can create a significant amount of stress. The same is true (albeit to a much lesser extent nowadays) for gay and lesbian individuals, and let's not forget that if you grew up, say, in the 90s, the world was still a significantly different place back then. As far as I know there have been studies showing increased stress levels in LGBT individuals even long after coming out.
In a sense, I often feel that trans people are now facing what gays and lesbians were facing a couple of decades ago. Let's hope that your road to acceptance will be as swift as it was for us.
The only thing that works with bullies, is ignoring them.
Trying to find reasons, psychological reasons, childhood traumas or gender identity issues, seems to be a way to focus on the behaviour and drama, instead of moving on.
As a trans person, I think there's a lot of toxicity to the online trans community, and there's certainly more prevalent mental illness (not surprising when you deal with frequent harassment, discrimination, being disowned by family). But trans people act like that because they feel like they're constantly under attack, and they have good reason to feel that way, given the flood of anti-trans legislation. That constant vigilance is exhausting, and as awful as it is, many of them (especially younger people) have limited power to protect themselves so they lash out at any perceived threat against trans people. It's toxic, and probably creates more enemies than allies, but I understand it.
A more interesting example would be toxic league of legends players. There's a few very popular, very toxic streamers (e.g. Tarzaned) who seem like they're struggling with depression or other issues.