Do you want to modify linetype scale in model space and paper space or other viewport the same? In this series, I will help everyone do this. You will be introduced two ways.
1st way: Use PSLTSCALE and REGENALL command in AutoCAD
In the Model space, you activate PSLTSCALE command and at the prompt, enter new value is o. after that you run REGENALL command.
2nd way: You click on Format > select linetype > show linetype manager dialog box > you don’t select “use paper space units for scaling” option > Ok
Linetype manager
My advantage that you should use 2nd way is good.
Video tutorial: