
Uday M. answered 07/30/19
M.S. Engineering, 5+ years of teaching experience
Yes, it is technically correct. "Extremely" is an adverb, meaning it can modify adjectives, verbs, or other adverbs. Both "appreciate" and "enjoy" are verbs, so the usage is appropriate. It is just awkward wording in the active voice. If you write it in the passive voice, it's a bit more palatable.
e.g. Your help is extremely appreciated.
However, it's still a bit awkward. This might be because "extremely" measures degrees of something. Appreciation is not typically measured by extent. There are some more common phrases that are used with appreciation that might be better suited for colloquial use.