You can manually install SketchUp 8 with PlayOnLinux manual installation. Download SketchUp, save to your desktop.
Click "install a non-listed program"
Follow the instructions for creating a new virtual drive, Wine configuration and version of Wine. I recommend downloading Wine 5.0 32-bit & 64-bit from the Wine Manager first. Also make sure you are using PlayOnLinux 4.3.4
When you get to the package installation, I would install the following:
The one critical library you need is Dot Net Framework 4.5.2 which may or may not install. I'm not sure if it will work in a 64-bit Wine, but you can try.