What is a word similar to "amateur" yet having a strong connotation of someone who likes something?

Solution 1:

Enthusiast does not connote unskillful, though it may retain the "non-professional" connotation of amateur:

a : one who is ardently attached to a cause, object, or pursuit
b : one who tends to become ardently absorbed in an interest (MW)

a person who is filled with enthusiasm for some principle, pursuit, etc.; devotee: a sports enthusiast. (RH)

Solution 2:

A possibly useful word for your case is hobbyist.

A hobbyist is someone who is interested or engaged with a field but specifically as a hobby and not a professional pursuit. It lacks the negative connotations of amateur, instead it has a casual implication.