For that case, you usually tile the texture. The basic idea is to draw the left part of the progress bar, then repeat the middle part until the desired length is reached and then draw the right part. What engine/framework do you use?
I use SwiftUI so I am a Mobile iOS Dev. In unity I would use tiles easily but in SwiftUI I need to do some workarounds :D
I mean, you could also fire up an image editing software like Krita and edit the progress bar into the desired length.
