Yeah, it's always a bummer to see a beautiful site design polluted by the ugliest of ads. But, you're selling those pixels to the highest bidder. So, not much you can do about it unless you want to start overzealously blocking certain ads, which will lead to less revenue.
On the upside, Google is pretty confident that whatever ads are showing on your site will lead to the highest Impression RPM. So, they're either being clicked on at a good rate, or are from advertisers who are paying a high rate for each click.
Also, I don't think advertising revenue is down that much, in general. For local advertising involving brick and mortar businesses, maybe. But, with more people staying home and on the internet, some niches have seen an explosion of revenue. It's not the same across the board.

Yes. I worked really hard on my websites and Adsense is the ugly part of them, not just in quality (content of the ads), but also in design, colors, look, and PERFORMANCE. Google Adsense is causing simple pages to weight a lot. I'm actually considering removing Adsense. Recently added a feature on my cms to turn on and off the ads on command.

I think a lot of the big players are really reducing ad spend, whereas some smaller player who are not perhaps as efficient at pricing their ads, are finding themselves getting a lot more exposure because they are now spending more.

Like every other market, advertising is in unprecedented times.

Mack.

Anecdotally I can say that all (low double digits) the SM influencers I am in contact with tell me that they’ve been inundated, since May/June, with placement and sponsorship queries.

Further, my advertisers have told me that they’ve either cut back web third third party advertising, shifted emphasis to targeted SM, to FB, or some combination.

As big money leaves a channel rates drop sufficient for smaller budget (sadly including bottom feeders) organisations. While this has been a trend/complaint for some time COVID is emphasising thE negative.

Until economies open up again, these diminished returns will continue.

Sadly, the better ads have checked (stopped) waiting for an open market which gives more space (and desperation to keep the pipelines full by ad agencies) to the second/third, or bottom tier advertisers.

Vicious cycle!