Yes, same here. For many years, I got like 0-10 messages in my Spam folder per week.
Then suddenly in maybe mid-December, an absolute flood started. I started getting at least 100 messages every day in Spam. Many of them were similar to each other, and nearly all of them were obvious spam like you say.
In the last week or two, the volume has decreased again to maybe 10-25 per day. I don't know if the spammers slowed down or Google tweaked something.
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Also, does Gmail route some spam to /dev/null and other spam to Spam? I somehow have the impression that it does.
That is, rather than doing a basic 2-way categorization (non-spam -> Inbox, spam -> Spam), it could be doing a 3-way categorization (non-spam -> Inbox, confidently spam -> Spam, undoubtedly spam -> /dev/null).
If so, I wonder if the issue could be with the confidently vs. undoubtedly categorization rather than necessarily an increase in total spam.