Saying “next to it/them”?

Question

I was wondering how you would say “next to it/them”, as I am confused whether to use “en” in place of “de”, or “de + lui/elle/eux/elles” or even another construction: “next to” translates as “à côté de”.

Normally, in phrases that use de, you can replace it with en to mean “of/about... it/them” instead:

J'ai peur du chien (I am afraid of the dog)
J'en ai peur (I am afraid of it)

However, with “à côté de”, I am struggling to see if you can use “en” here, or “de lui/elle/eux/elles”. Take the following:

Le canapé est assez grand, et à côté du canapé il y a une télévision
The sofa is quite big, and next to the sofa there is a television

The problem with the above sentence is that using “next to the sofa” twice sounds ridiculous. As a result, I was wondering how to say “next to it”, so that the English could be rephrased to:

The sofa is quite big, and next to it there is a television

I have two ideas, but am not sure whether either are correct (the second, using “en” sounds wrong in my opinion, though)

Le canapé est assez grand, et à côté de lui¹ il y a une télévision
Le canapé est assez grand, et en à côté il y a une télévision

—
^{1. “lui” being because canapé is masculine.}

Answer 1

First, as you mentionned Canapé is masculine:

Le canapé est grand .

As for your question "et en à côté" does not make any grammatical sense.

Your first instinct (and sentence) is grammatically correct,

Le canapé est plutôt grand et à côté de lui il y a une télévision.

Because the only other item mentionned in the sentence is the canapé and that "television" comes immediately after you don't even need to use any pronoun.

Le canapé est plutôt grand et à côté il y a une télévision.

Though, as a native speaker, I'd say something more like

Le canapé est plutôt grand, et il y a une télévision juste à côté.

Bringing "television" even closer to "canapé" leaves no doubt as to what the television is next to.

Answer 2

En can only replace de + noun, not de + pronoun. In addition, it always follows a subject and precedes a verb - it can't follow a preposition.

For example,

*Il a acheté deux stylos - Il en a acheté deux.

Voulez-vous encore de vin ? - Merci, j'en ai assez.*