I'm excited for new features in Safari. Apple added support for web extensions last year and has slowly been adding new features to Safari. Hopefully we can get feature parity with Chrome and start getting a fraction of Chrome's extension library.
It would be great if they finalize the loading="lazy"attribute. Safari is the last holdout amongst the big browsers for this (for images) and I look forward to removing lazy loading javascript from my website.
I'm hoping Safari gets on the vertical tabs bandwagon. Currently Edge and Vivaldi have this as options but I don't think either has nailed the implementation. Feels like something Apple would probably get right.