The dotted or thickly dashed display of solid lines, arcs and texts in AutoCAD is caused by graphics card incompatibility.
If you are using a desktop or laptop computer with a dual graphics cards (equipped with an NVidia or AMD graphics accelerator in addition to the integrated graphics), make sure AutoCAD is running on the accelerated card.
For NVidia cards, use the NVidia Control Panel to do this and select the accelerated mode for AutoCAD. For AMD Radeon cards, add AutoCAD as a "gaming software" in its control panel. In Windows 10 and 11, use "High performance" setting for AutoCAD in Graphics Settings > Graphics Performance Preferences:
If the settings won't help, in AutoCAD, in the GRAPHICSCONFIG command dialog, select the "Basic Mode" option in the "2D Display Settings":