The wiki says that junction=yes by itself is pointless, it doesn't indicate anything. Tagging junction=yes means just as much as the bare node itself.

If you want to indicate directions, you need more than that, which is what a manoeuvre relation can be used for. Without having information about which ways are actually joined, how can any kind of routing algorithm know what is actually meant?
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            Published using OSMCha: https://osmcha.org/changesets/149827539
            