I haven’t hosted something big in the past but I have dabbled sometimes

The ssh knockers have always been there. But now the blocklists are either more accessible or I just have heard about them more in the meantime

Scrapers did not use to DDoS so aggressively but also have been there. Now we have the challenges (anubis, cloudfront, captchas) to mitigate their hunger (and the blocklists)

What has changed is that now one needs to remember what a piece is written in. A PHP vulnerability one day, Go another. And everytime one has to run through the list “what the stuff we’re hosting is written in”. But personally, I think this will pass. What is being discovered right now are often long-standing bugs, so the only mitigation is update. Once the vulnerabilities are coming from a recent change, sometimes it will be patched before we need the newer version of a library