It's an excellent question @Yamin. Fulfilling the mitzvah of tefillin is actually equated with fulfilling all the miztvot of the Torah like is found in Kiddushin 35a in the name of Rav Acha bar Yaacov. This is also taught in Sefer Reishit Chochma by Rabbi Eliyahu DeVidas and Kitzur Shulchan Aruch, Siman 25:1.
It is significant to emphasize that the citation from Kiddushin does not use the term 'shikool', which means of equal value but not actually the same thing. Rather it uses the uses the expression 'hookshah', which has a meaning of actually being one, like two hands being struck together as one.
To explain this in more detail requires citing the explanations of numerous Siddurim, like the Siddur of the Ramchal, the Siddur Kol Yaacov, the Siddur of the Ari and others concerning the intentions, the 'kavannot', of the prayers.
When one lays tefillin, it begins with the 'tefillin shel yad'. This is because we are reminded that the action, performing the mitzvot through action is the primary aspect as opposed to just contemplation. (המעשה הוא העיקר)
When one puts on tefillin, part of that process is to gaze at the two 'Shins' on the 'tefillin shel rosh'. While gazing, it is noted that one of the 'Shins' has three heads and one has four heads. Three plus four equals seven. And the two 'Shins' together spell the word 'six' (שש). Seven plus six equals thirteen. But the letter 'Shin' also has a numerical value (
gematria) of three hundred. And so the two 'Shins' also convey a meaning of six hundred. The total so far is six hundred and thirteen (613). This equates with the 613 mitzvot of the Jewish people. (תרי״ג מצות בני ישראל)
But it doesn't stop there. 'All the mitzvot of the Torah' also includes the 7 mitzvot of the children of Noach (שבע מצות בני נח) which parallel the 7 Rabbinic mitzvot (שבע מצות דרבנן). These are brought to mind through the 'batim', the houses of the tefillin. The 'tefillin shel yad' has a single bayit (1). And the 'tefillin shel rosh' has four batim (4). Unlike the mitzvah of tzitzit (the blue and white fringes) which are considered a single mitzvah, the 'tefillin shel yad' and the 'tefillin shel rosh' are considered two separate mitzvot (2). This reminds us of the additional 7 mitzvot (1 plus 4 plus 2).
And the inclusion of the two categories together (613 and 7) gives a total of 620 (כתר, crown 'of G-d's Kingship') which alludes to the revelation of G-d's kingship over the entire universe. (מלך העולם)
This is also the idea that 'G-d is one and His name is one.' And this is recalled while reflecting on this unity because placed within the 'batim' of both the 'shel yad' and the 'shel rosh' are the same four parshiyot. In the 'shel yad' they appear on a single klaf and in the 'shel rosh' they are on separate klafim. And this is where the eight (8) is found in the tefillin, meaning in the total number of parshiyot. The one 'bayit' of the 'shel yad' (1, א), the eight parshiyot from both the 'shel yad' and the 'shel rosh' (8, ח) and the four 'batim' of the 'shel rosh' (4, ד). Together, this is 'One' (אחד). Hear Israel, the L-rd, your G-d, the L-rd is one.