Not a big enough sample to draw such conclusions… He clearly didn’t give a shit about scoring for United over the last 3 months. The minutes he played for Portugal he seemed capable of creating himself chances and potentially scoring.
His decline started in his last season at Juventus. And he still won Euro and Serie A golden boot that year(both for the first time, I believe). But even that version of him (with less assists) managed to keep his floor at 30 in all competition (Portugal included) over his first season with us, and he was in the PFA team of the year.
Until last season -while becoming less useful in the build up- he kept his scoring record very high. I doubt he’s lost too much of that in the last few months.