May This reach you in great health and imaan,
I heard recently a Salafi Sheikh being asked about Meditation (focusing on breath and mindfulness-awareness) and he said ‘we are not buddhist we do not meditate’ however I find that though Buddhism does emphasize different types of meditation, but so do many other traditions. I dont find it evil for one to sit quietly and breath in and out (properly). This practice increases the vibrant action of the cells in the body, it changes the brain waves positively, it gives longevity, it helps one focus throughout the day on duties, etc.
So how can sitting and meditating be haram?
Let alone Salafis, they got a purified heart and do not need Tazkiyah whereas it was one the duties of the Nabee of Allaahﷺ. Tazkiyah has no particular form. It can be performed in any form provided that the form is not specific for any other religion and one does intend to emulate them.
There are two conditions for Tashabbuh; 1) intention and 2) the thing is specific for the others.
As regard to meditation, is of different types. Therefore, nothing wrong if one sits facing the Qiblah,if possible, closes his eyes and performs Zikr in a way that when he breathes in, he imagines that the word Allaah penetrates the depths of his heart and when he breathes out, the word ‘HU’ strikes the heart.
والله اعلم بالصواب