Real Madrid releases a PDF every year covering the club’s activities and successes, but also importantly laying out all their financials. Florentino and the board have done an incredible job of diversifying the revenue streams - per graphic below (1/7):

They are much less reliant on television revenue and stadium income than they were in the past. But it still makes up 38% of their revenue. If La Liga was cancelled, that revenue loss could be as high as 60%. Obviously wasn’t the whole season, so adjustments to the figures (2/7):

would need to be made, but needless to say if COVID-19 has impacted the world’s most valuable club (and one of the most fiscally responsible clubs) think about the smaller clubs who rely entirely on stadium and TV revenue. (3/7):

I cannot stress enough how different the transfer market will be over the next few years.

Players swaps, loans, and longer contracts to amortize the transfer fee to a smaller annual figure will be the new norm.

(4/7):

I mean the club even goes as far to release their budget for player sales each year. It will be extremely extremely difficult to hit that €94M transfer profit budgeted. So how do you off-set that? By not expending capital on new players. All clubs will be in the same boat.(5/7):

RM also released their figures for investment in their facilities which was around ~€20 million. Llorente and Morata together have paid for four years worth of facility upgrades. Investing in your infrastructure and specifically your academy reaps an unfathomable ROI.
(6/7):

For those that want to read the PDF in detail - which I highly recommend - use the link below (7/7):

https://www.realmadrid.com/media/document/annual-report-real-madrid-2019.pdf