Again, that's all based on what he said in the Variety interview to promote his Moses movie. I linked it above. Anything you're going to read elsewhere is based on this teensy bit in that interview where he's asked about Blade Runner 2. Here's the bit about him not directing:
Per Scott, that Alcon Entertainment production should go before the cameras within the next year, but with someone else directing (he’ll produce).
Ridley Scott does not decide what movies get made. The funding his production company secures decide what movies get made. What he's been trying to do is drum up some funding, and idiotic bloggers gladly pass along his comments as if they were articles in Variety, which leads to people on message boards who don't know a sourced article from a blog entry to talk about it like it's an Actual Thing. Ridley Scott has even drafted Harrison Ford for the project with, as far as I can tell, nary a word from Ford himself.
Unless I'm missing something, the Blade Runner sequel is in the same boat as the Prometheus sequel.