Sketcher works slowly with the complex sketch in Creo 4.0 M150

Some articles about slow response in Creo 4.0:
https://www.ptc.com/en/support/article/CS288477 
https://www.ptc.com/en/support/article/CS268086 

In general it is not considered best practice to have complicated sketches. Can you do it with multiple simpler sketches?

Can you use symmetry to work on a smaller portion of the sketch and then mirror?

I would get rid of the edge references they slow things down.

Consider alternate methods to capture design intent for your sketch(es). This looks like a good candidate for using the top down design tools to pass geometry from one model to another. Copy geometry features look like a good choice. Creating a sketch in the context of an assembly model will create an external reference to the assembly which in general is not desirable. If you are referencing multiple components in a single sketch you should avoid that if possible.

I would use external copy geometry functionality to get the references into your part model. You can then use them in your part and break it down into multiple sketches. You should see a much faster regeneration time using this method.

As mentioned above, complex sketches are not optimal. Use multiple features with simple sketches.