To be honest, I don't want Millan to win the green jersey. He would be such an underwhelming winner.
The problem is the green jersey has become something of an underwhelming competition, quite often won by default if there is no dominant sprinter, and because it is weighted toward flat stages, often the sprinters get stage wins in and of themselves as a reward and aren't as bothered by the maillot vert competition, so it isn't often we get what I'd call a genuine competition for the jersey; the most interesting recent competition for green to me was 2020 with Bennett trying to get stage winning chunks and a not-quite-at-his-best Sagan trying to manoeuvre into a win by making undulating stages hard to drop Bennett, or drilling the echelons all day in stage 7 (which had a positive effect on the GC race as well as a bonus effect), and then that was taken away prematurely after Sagan got a relegation and Bennett's lead became too much to catch back up.
Obviously van der Poel rather fits the profile of most recent winners of the jersey to fit in the heritage of a jersey won more commonly by World Champions and classics-adept sprinters rather than pure sprinters (while the Cavendishes and McEwens of this world have green jerseys, there are more of the Boonen, Hushovd, Freire type) better than Milan, with Sagan the record winner and van Aert's recent wins, but during Sagan's time he would gain points the way MVDP is doing, but also be more competitive in the bunch sprints so he could collect points in big chunks in the 50-pt stages as well as the lower point level ones.
Perhaps Milan might not feel right because of the profile of winners, but it's not that different to how Thor Hushovd won it in 2009 (save for that solo break exploit in the queen stage, which is mostly what is remembered about it), just collecting points for positions behind Cavendish, or even how some of Sagan's points jerseys were won, because the thing with a lot of those was that the competition was dead by this point in the race because none of the sprinters could gain enough on Sagan in the sprint stages - even after the points system was changed to explicitly favour flat stages even more - to cover their deficits in the intermediate and mountain stages he could win at least the intermediates in, and would open up a lead that meant he only needed to manage the score the rest of the way. Hell, Ale-Jet Petacchi did the same in 2010 before the points system was changed - but both are high profile enough as riders for sprints and one-day races that they don't stand out as a surprise on the list of jersey winners the way, say, Baden Cooke does.