It sounds like you have already observed that your activities do not seem to change your symptoms. If you add some more strenuous activities and your symptoms do not increase, then why not do those activities?

Be aware of your risk of Second Impact Syndrome and Multiple Impact Syndrome. There are many here on NT who have lifelong issues due to Multiple Impact Syndrome. Be aware that your surfboard can whack you in the head so big wipe outs might be worth avoiding.

Regarding depression. Depression is a physiological illness cause by emotional and/or physical stresses. The emotional stresses can all be positive and still cause depression. Depression is common in the PCS community due to the physical stresses put on a brain that is less tolerant. Add just a bit of emotional stress and you have a double whammy of causes. You are very fortunate to not be experiencing depression.

My concussions have caused a roller coaster of depression after each concussion.

Just remember. You have a whole life to live. Short term risks can cause a lifetime of struggle.

My best to you.