Snaking a shower drain is a temporary relief just like chemicals.
The shower drain pipe normally 2″ diameter and gets encrusted with soap scum and other debris build up.
Snaking only punches a small hole and is not capable of restoring full flow as intended.
Call a Licensed Plumber NOT his helper and ask to see the license before the work is started.
Many of the union helpers have NO PRACTICAL experience other then possibly getting coffee for the troops or cleaning up after a journeyman.
When the licensed professional arrives they should water jet these lines to a full flow condition.
Now for your information IF a line is totally blocked say from hair or other HARD stoppage like rags, etc., then a snake is ideal BUT you said this drain was sluggish
That alone proves your piping has been diminished in size.
Like they say Never hire a Helper to do a skilled persons Job.
Your better off renting a small electric jetter rather then EVER letting any helper dabble in your home.
Here is a good article for you to read.
Good luck