Late 2027 or 2028 most likely. MacOS version lifespan is about 3 years give or take so we'll have a better idea once they announce whether or not MacOS 16 (Sequoia's successor) will support Intel Macs.

I have a hunch we'll get one more MacOS version with Intel support since they were still making Mac Minis and Pros with Intel chips in the first half of 2023.

any day now, usually after 6-7 years after hardware releases.

We probably have a few more years to go then. Consider that they were still selling Mac Pro 2019 Intel systems as late as June, 2023.

I'm not convinced this year's OS release will support Intel. When they switched to Intel, Apple was quicker to dump PowerPC than people remember.

I'd be surprised if they don't support it for at least one more release. With Intel, they discontinued the PowerPC systems much faster (by the end of 2006.) They were still selling Intel hardware 2 years ago, a couple years into the ARM / Apple Silicon transition.