Help with editing an STL file

Not sure if this is the right place but I don’t know where to post this question.

I’m learning how to edit an STL file (shown in the picture as I couldn’t upload the STL probably due to size)

I have tried both Meshmixer and Blender so far but no luck. Basically I want to flatten the two bottom straps of the ribbon, which are tilting backwards now if you look from the front.

Really appreciate if anyone can point me to the right direction, maybe a tutorial or something that teaches how to do that.

Depending on how flat you want it’s probably easier to cut them off and model a new bottom section. Otherwise it’ll be a lot of nudging in Meshmixer, ew.

Tinkercad, Blender, F360, would be my top choices

Probably too large of a file for tinkercad. But it would be worth a try.

So far this has been the hardest thing to figure out. Meshmixer isn’t really intuitive. (I need to sit down with some tutorials and figure it out)
Blender is probably the best for more organic shapes like that.