“LU, there si no Torah like the Torah of Eretz Yisrael. In fact, Chazal say that if one lives in Shmutz laAretz it is if he has no Gd and it is as if he commits idolatry (Ketubot 110b). Ramban says (Vayikra 18:25) that we only do mitzvot there in order not to forget themThe Gra says (Likutim on Sefer HaTzeniuta) that it is a graveyard for Jews. It follows that a Jew there is considered dead.”
I am well aware of all that and I am well aware that the ideal is to live in Eretz Yisrael (which is why I’m here, Boruch Hashem). However, it does not follow that every Jew is obligated to or even should live in Eretz Yisrael.
It is also an ideal to learn Torah full-time, but there are times when it would be a big aveira for someone to be learning.
All Mitzvos can be made into “avoda zara”. All Mitzvos can be done in the wrong way or in the wrong time. We are not supposed to worship anything but Hashem and that includes not taking any Mitzvah out of the context of Avodas Hashem.
There is a famous story about a meeting of Rabbanim to save the Yidden (maybe during the Holocaust?). One man got up and said, “We must daven Mincha or we will miss shkiya.” One of the Gedolim who was there said, “We are in the middle of saving lives. It is assur to daven Mincha now, and anyone who joins that man in davening Mincha is a murderer.
That is the classic example of using a Mitzvah as avoda zara. The Mitzvos don’t have inherent value in themselves but only as tools to serve Hashem and they are only tools to serve Hashem when they are kept the way Hashem wants. Every Mitzvah has parameters – times and ways that it is supposed to be done and times and ways that it is forbideen.
Your tzitzis example is a great example. If you were to ask me if it’s a Mitzvah to wear tzitzis, I would say yes. But if you were to ask me if it would be a Mitzvah for me to wear Tzitzis, I would have to say no. In fact it is proabably assur for more than half of Am Yisrael to wear Tzitzis. Less than half of the Frum members of Am Yisrael wear Tzitzis (none of the women as well as boys under 3). And even men and boys over 3 are not obligated to wear Tzitzis at certain times of day (namely at night).