Breaking the rule of thirds?

It's not a rule, it's a suggestion. There's no must about it.

I've a feeling this rule came about because many beginners tend to place the main subject dead-centre in their pictures. So the idea is to gently lead people away from that habit.

But as soon as you know about this idea, and are familiar with it, then you are free (and encouraged) to ignore it. Use whatever composition works best, whether that means putting your subject in the middle or right at the edge, use them all, don't be limited.

Sticking rigidly to the "rule" of thirds is at least as harmful as always placing the subject in the centre. The idea is to use your own judgement of what works.

Regards,
Peter