The Mishkan and Beis HaMikdash are central points in our belief system. It is not for Hashem, who doesn’t need a particular location to be in our lives; he is everywhere.
The initial instruction says what it’s for. its for us וְעָשׂוּ לִי, מִקְדָּשׁ; וְשָׁכַנְתִּי, בְּתוֹכָם- It is for us, and lets us know that He is with us.
Rav Hirsch teaches that וְשָׁכַנְתִּי בְּתוֹכָם is about God’s proximity to prosperity in all areas; national and personal. Just as in the Shema, the scope of the Jewish mission transcends the sum of it’s parts. It is not enough to tick off the laws we follow, the plans we carry out, or the animals offered.
The Mikdash represents the dedication to the collective mission that we build, as individuals and as a nation, and the result of carving out a dedicated space is God’s closeness. It is a mutual covenant.
Finding God and goodness requires action from us. Beyond sacrifices and rituals, what is required is a home in our lives. The space we turn into a Mikdash is the one that God will see as His Mishkan.