I’m drywalling my attic.  I know there’s movement and I need something that can take it.  Thought about trim-tex magic corner but I could use something with wider flanges and the rubber bit in the middle seems weird for finishing.  Heard about no-coat ultraflex but it looks like no-coat got bought out by certainteed.  Is ultraflex now just no-coat flexible corner?  Is it made to withstand movement like magic corner does or just getting beaten with a baseball bat like they show in their youtube videos?