Fat Rider, Need Advice

Hey Guys, first post. I've searched around but can't find anything related to my size. I might be too big for the bike but that hasn't stopped me yet. I love the darn thing.

2021 9T Roadster.

I want to upgrade the suspension. Mainly the rear feels pretty bad. I weigh 340lbs, im 6,4 so I'm a big guy. Is there any suspension parts that you think would work for me? I'm a newb.

Thanks!