I'm won't believe winter schedule until it happens.
Well as it sits now the 2022 world cup break would be during the end of the regular season and entirety of the playoffs. That certainly won't fly so they will have to start the regular season a month and a half earlier, in mid-January. If/when this happens it will have to be a multi-year process of the season starting a couple of weeks earlier each year likely starting in 2019 so that they don't have the MLS Cup in December and then starting the next season six weeks later.