The answer is no, you can’t just choose whichever one. My first feeling is that when it comes to verbs expressing likes or dislikes, if the object is a person or something that can be personified or is closely linked to a person, I would use je l’aime, or je le/la déteste

I’ll give you a few examples :

• La salade, j’aime ça.

• Conduire, je déteste ça.

• Quand on m’amène le petit-déjeuner au lit, j’aime ça.

• La poésie, j’aime ça.

as opposed to :

• La poésie de Baudelaire, je l’adore.
• La musique de Chopin, je l’aime.
• La France, je l’aime.

And a fortiori :

• XXX (somebody’s sweetheart), je l’aime.

You use "j’aime ça" when it refers to an action. So when there is a verb in your preposition. Example:

J’aime sortir avec Christelle.

Sortir avec Christelle, j’aime ça.

So you use "je l’aime" in other cases. Example :

J’aime Christelle.

Christelle, je l’aime.

J’adore la poésie de Baudelaire.

La poésie de Baudelaire, je l’adore.

the difficulty with "j’aime ça" is that sometimes the verb is implied in the preposition:

J’aime manger de la salade.

La salade, j’aime ça. (Manger de la salade, j’aime ça.)

J’adore lire de la poésie de Baudelaire.

La poésie de Baudelaire, j’adore ça. (Lire de la poésie de Baudelaire, j’adore ça.)

So, if you want to know when to use j’aime ça or je l’aime, you put the sentence in the right order. If you say I like + something or someone, you use it "je l’aime". and if you say I like + verb + something or someone, you use "j’aime ça".

J’ai ça/ je l’ai.

"J’ai ça" is never used in French unless you want to say that you have something that you point to. Indeed, the verb to have is particular.

Otherwise, apart from the verbs of feeling (to love, to hate, etc …) and the verb to have / to be.
you can use both indifferently but still prefer the "l’" to "ça".