Based on the origin spring shock
Since it is tricky to print , I try to separate it into several parts.

In the shock-all.stl, it is the recommended print direction, I have made the cap a bit bigger, in order to insert the tube easier.

Use a 8 mm M2 screw to connect the head and the shaft inside the tube.
Glue maybe necessary with the tube and the cap. Adapt grease inside the tube

If installing the spring inside the tube, the spring should be 5 mm outside diameter, length is about 30 mm.

And I designed a spring hold to installed on the shaft, the bigger spring now is in order to be installed outside.
The spring's inside-diameter (outside-diameter minus double wire-diameter) should be between about 9 mm-10 mm in order to keep the spring flexible and do not exceed the hold and cap diameter. The length is about 40 mm.
For example I have tested spring 0.6 x 10 x 40 (inside diameter 8.8 mm) , it works but the spring is a bit too strong, maybe 0.4 wire would be fine.

Since it is nearly the Spring Festival Chinese New Year, it is hard to get a new spring, I will test the spring later.
And Happy Chinese New Year.