A few things happened pretty quickly.
During the pandemic, tech profits soared which led to massive hiring sprees. For all the press about layoffs at the big guys, I think most still have more workers than they did pre-pandemic.
Interests rates soared. Before the pandemic interest rates were ludicrously low, in other words it cost almost nothing to borrow money. This made it easier to spend on long term or unclear projects where the hope seemed to be "get enough users, then you can monetize." Once interest rates rose, those became incredibly expensive projects, so funding is now much more scarce. Companies are pulling back on bigger projects or, like reddit, trying to monetize them faster. Startups are also finding it harder, so fewer jobs.
And of course, AI. No one is quite sure how much that'll change the game but some folks think most programmers will be replaceable, or at least 1 programmer will be able to do the work of several. So, rather than hire and go through everything severance etc might entail, I think a lot of companies are taking a wait and see approach and thus not hiring.