Xjyuk

Is it possible to know what G-d was doing before this creation?

While, as Maimonides states, that we cannot know anything about G-d except for what G-d is not (G-d has no body and is one), nevertheless, I think the question remains, and can be boiled down to this: are there any sources explaining what G-d might have done before creation of the world (i.e. was G-d forming past worlds in an endless cycle, as in preforming His creative energy?) Think of reincarnation but on a larger scale, namely, the universe. Indeed some scientists think this was the case before the Big Bang. If true, it would entail that this world-building will continue to occur. What were our sages' opinions regarding this?

I could point you to Shabbos 88b below, but please clarify if you are asking about what occurred prior to 974 generations before the creation of the world.

ואמר רבי יהושע בן לוי בשעה שעלה משה למרום אמרו מלאכי השרת לפני הקדוש
ברוך הוא רבונו של עולם מה לילוד אשה בינינו אמר להן לקבל תורה בא אמרו
לפניו חמודה גנוזה שגנוזה לך תשע מאות ושבעים וארבעה דורות קודם שנברא
העולם אתה מבקש ליתנה לבשר ודם מה אנוש כי תזכרנו ובן אדם כי תפקדנו ה׳
אדנינו מה אדיר שמך בכל הארץ אשר תנה הודך על השמים

And Rabbi Yehoshua ben Levi said: When Moses ascended on High to
receive the Torah, the ministering angels said before the Holy One,
Blessed be He: Master of the Universe, what is one born of a woman
doing here among us? The Holy One, Blessed be He, said to them: He
came to receive the Torah. The angels said before Him: The Torah is a
hidden treasure that was concealed by you 974 generations before the
creation of the world, and you seek to give it to flesh and blood? As
it is stated: “The word which He commanded to a thousand generations”
(Psalms 105:8). Since the Torah, the word of God, was given to the
twenty-sixth generation after Adam, the first man, the remaining 974
generations must have preceded the creation of the world. “What is man
that You are mindful of him and the son of man that You think of him?”
(Psalms 8:5). Rather, “God our Lord, how glorious is Your name in all
the earth that Your majesty is placed above the heavens” (Psalms 8:2).
The rightful place of God’s majesty, the Torah, is in the heavens.

This is one of the topics that one should avoid discussing. See Mishna Chagiga 2:1, 11b in the Talmud:

אֵין דּוֹרְשִׁין בַּעֲרָיוֹת בִּשְׁלֹשָׁה. וְלֹא בְמַעֲשֵׂה בְרֵאשִׁית
בִּשְׁנַיִם. וְלֹא בַמֶּרְכָּבָה בְּיָחִיד, אֶלָּא אִם כֵּן הָיָה
חָכָם וּמֵבִין מִדַּעְתּוֹ. כָּל הַמִּסְתַּכֵּל בְּאַרְבָּעָה
דְּבָרִים, רָאוּי לוֹ כְּאִלּוּ לֹא בָּא לָעוֹלָם, מַה לְּמַעְלָה, מַה
לְּמַטָּה, מַה לְּפָנִים, וּמַה לְּאָחוֹר. וְכָל שֶׁלֹּא חָס עַל
כְּבוֹד קוֹנוֹ, רָאוּי לוֹ שֶׁלֹּא בָּא לָעוֹלָם:

They may not expound upon the subject of forbidden relations in the
presence of three. Nor the work of creation in the presence of two.
Nor [the work of] the chariot in the presence of one, unless he is a
sage and understands of his own knowledge. Whoever speculates upon
four things, it would have been better had he not come into the world:
what is above, what is beneath, what came before, and what came after.
And whoever takes no thought for the honor of his creator, it would
have been better had he not come into the world.