Did some more digging into 2025 transactions.
Per NFL.com, SF placed Aiyuk on the "Reserve/Physically Unable to Perform" list on 8/26/25.
Per CBS.com, SF then moved him to the "Reserved/Left Camp" list on 12/13/25. Oddly, NFL.com does not list this transaction, but does currently shows his status as "Not With Team."
So it does look like the Aiyuk situation would currently be subject to the 'roster/salary cap not affected, contract does not exist' rule discussed previously.
No idea why Aiyuk has not reported, to force a status change and pressure the team. Of course, setting fire to $30M (and growing?) doesn't make any sense whatsoever either, so who knows what he's thinking.