You make a fair point about using Allah when speaking English, but other than in this I would speak (or attempt to speak) in Arabic when using my Tasbih (the content of which is not exclusive to Islam).
Also, even though Arabic isn’t the divine language, it still certainly is beautiful. Take the phrase “La illaha illa Allah”, just a series of al’ and 'la sounds and we get that elegant Truth that there is no god except God. VERY POETIC
The gold mask of Tutankhamun is very beautiful. But it doesn’t belong in a Catholic sanctuary.
The Popl Vuh is very poetic, but it doesn’t belong in a Catholic liturgical reading.
There is a venerable old saying in the Church that can even be found in the Catechism: “Lex orandi, lex credendi,” The law of prayer is the law of belief. It means just that - The manner in which we pray will inform what and how we believe.
Thus, to be Catholic, we must pray like Catholics.
There is absolutely no good to be found in the religion of Mohammed that cannot be found in the Catholic Church. If you had a choice between clear, clean drinking water and a spring that contained, in addition to water, a certain amount of poison, why would you slake your thirst in the latter over the former? Even if the spring contained only trace amounts of poison… why choose it over clean water?
The Islamic chaplet to which you refer is essentially a Mohammedan copy of the ancient Christian Kombologion (100 beads, used to mark 100 repetitions of the Jesus Prayer). This is a genuine Christian prayer of ancient and venerable pedigree. Why not incorporate it into your prayer life rather than an anti-trinitarian bastardization of it?
“There is no God but God” can, in the abstract, be stated in a perfectly orthodox Christian sense. So why should we not use it? Because it is a specifically islamic formulation, formulated by and for men who view God as “one” in a sense that totally rejects the Holy Dogma of the Trinity. Therefore it should be avoided altogether and not incorporated into Christian prayer - Lex orandi, lex credendi.
Talk to a good, orthodox Catholic priest about this as soon as possible (emphasis on “good” and “orthodox”).