pekudei - How could there be so little gold in the Mishkan, when it’s clear there’s much more?

In Shemos 38:24, we’re told that:

כָּל־הַזָּהָ֗ב הֶֽעָשׂוּי֙ לַמְּלָאכָ֔ה בְּכֹ֖ל מְלֶ֣אכֶת הַקֹּ֑דֶשׁ וַיְהִ֣י ׀ זְהַ֣ב הַתְּנוּפָ֗ה תֵּ֤שַׁע וְעֶשְׂרִים֙ כִּכָּ֔ר וּשְׁבַ֨ע מֵא֧וֹת וּשְׁלֹשִׁ֛ים שֶׁ֖קֶל בְּשֶׁ֥קֶל הַקֹּֽדֶשׁ׃

All the gold that was used for the work [in the Mishkan], in all the work of the sanctuary—the elevation offering of gold—came to 29 talents and 730 shekels by the sanctuary weight.

Rashi defines a “talent”:

ככר. שִׁשִּׁים מָנֶה, וּמָנֶה שֶׁל קֹדֶשׁ כָּפוּל הָיָה, הֲרֵי הַכִּכָּר ק"כ מָנֶה, וְהַמָּנֶה כ"ה סְלָעִים, הֲרֵי כִּכָּר שֶׁל קֹדֶשׁ שְׁלֹשֶׁת אֲלָפִים שְׁקָלִים

”A talent” - 60 [common] Maneh. The Maneh of the Sanctuary was doubled; thus a talent is 120 [common] Maneh. A Maneh is 25 Sela [the Talmudic equivalent to a Biblical Shekel], thus a Sanctuary talent was 3000 Shekalim.

Kiddushin 12a states that there are 1536 Perutos in two Sela, or 768 Perutos in one Sela. A Perutah is 0.025g according to the Shulchan Aruch (CM 88:1), or 0.018g according to Rashi (Bechoros 49b), leading to a Sela being 19.2g according to the Shulchan Aruch or 13.824g according to Rashi.

The total gold in the Mishkan, then, was either 1,684.416kg according to the Shulchan Aruch or 1,212.77952kg according to Rashi.

Now, my ballpark estimate of just the gold in the Aron yields at minimum 3,565.97kg, over double the Shulchan Aruch’s number for the total gold in the Mishkan, and close to triple Rashi’s number!

I see that this issue was raised by the Ralbag.

Does anyone reconcile these numbers?