I am trying so hard to go to the gym or practise exercise at home but I always have an excuse for not doing it (like improving my English writing this xD)

We never say “practice exercise”: it is always used as a gerund or by itself:

“I hate exercising.”

“I am going to exercise.” <- “Voy a hacer ejercicio.”

So, where is theWhere has my motivation? gone?

So = así que in English. From my understanding, you need a statement + so + contrary information/conclusion. Your original sentence would make sense like this, for example:

“Exercising has major health benefits and improves your mood. So, with all these in mind, why do I struggle to… find the motivation?/keep myself motivated?.”

Whereat is the point that you put on yourof putting on gym clothes and start doing the exercise?

What = define
Where = define location
We always say “What is the point”.

I have thought many times about this, and many times, and I have taken the decision to domany steps towards it, but, in the end, I still keep my body in the chair oralways end up on the sofa.

I would just pick one (sofa/chair); I would suggest sofa as in our culture we have “couch potato”; a saying meaning a person who is resigned to the couch instead of action.

I am trying so hard to go to the gym or practise exercise at home, but I always have an excuse forto not doing it (like improving my English writing this xD)

practise exercise - "to exercise" on its own is a verb, and sounds more natural.

"I have an excuse for not... " vs "I have an excuse to not... " are both correct, but I wanted to show you another way to phrase it that is shorter and more natural.

Where is theAt what point thatdo you put on your gym clothes and start doing the exerciseing?

"at what point" is an expression that basically just means "when", but sounds a little more demanding.

"doing [noun]" or "doing ___ing" will always be less natural than just "___ing", if the verb means the exact same thing. For example: "doing biking" is less natural than just "biking". Less is more!

I have thought many times about this, and many times I have taken the decision to do it, but in the end, I still keep my body istay on the chair or sofa.

I actually liked "I keep my body" because it sounds funny and super dramatic. I suggested "stay on" because it's more concise (again, less is more!). Also, it's "on" and not "in" - think of "on" as "on top", and "in" as "inside". "In the sofa" sounds like the sofa ate you and you are inside of it 😂

I am trying so hard to go to the gym or practiseto exercise at home, but I always have an excuse for not doing it (like improving my English writing this xD)

Where is the point that you put on your gym clothes and start doing the exerciseing?

I have thought many times about this, and many times I have taken the decisiondecided to do it, but in the end, I still keep my body glued to/deep in the chair or sofa.

I am trying so hard to go to the gym or practise exercise at home, but I always have an excuse for not doing it (like improving my English writing this xD)

Where is theAt what point thatdo you put on your gym clothes and start doing the exercise?

I have thought many times about this, and many times I have taken the decision to do it, but in the end, I still keep my body iyet I always end up sitting on the chair or sofa.

I am trying so hard to go to the gym or practise exercise at home, but I always have an excuse for not doing it (like improving my English writing this xD).

Where is the point that you put on your gym clothes and start doing the exercises?

alt:
At what point do you put on your gym clothes and start exercising?

I have thought many times about this, and many times I have taken the decision to do it, but in the end, I still keep my body in the chair or sofa.

alt:
but in the end, my body stays glued to the chair or sofa.