I agree.
And I see no reason for Thanos being weaker in 2014 than he was in 2018. Fully-grown men don't generally change strength over the course of four years - unless, of course, they've trained and visibly gained muscle, which Thanos hadn't by 2018.
More to the point, four years is a MUCH smaller fraction of Thanos' life than the average man. Judging by how much Titan had deteriorated since he left - and, presumably, given that he was already an adult when he did leave - he may well be thousands of years old. Four years certainly wouldn't have made much of a difference.