Simple case for a single Mini-CD, Mini-DVD, ... (80mm)

No support needed.

I have print the layers of the “inlay” between 1.2 mm and 3.0 mm with 0.1 layer height, everything else with 0.2 mm layer height.

I also suggest to use more top layers, wall loops and infill.
(e.g. 4 top layers, 3 wall loops and 25% infill)

(ca. 25g filament needed)

For transparent prints with PETG, follow the recommended settings such as those from https://wiki.bambulab.com/en/knowledge-sharing/transparent-petg.