>>45477227Cover probably made her record about 500 hours of various things in advance. Not just because they want it all right now but for future things and because... well, just in case they don't get that chance again.
And then other holos probably made Gura record duets for their own upcoming 3D lives and anniversaries throughout the year.
And THEN you also have all kinds of companies paying Cover to buy Gura time for ads and sponsorships which she had to record as well.