I’m not quite sure what you are seeing. What website are you using?
When I look, tickets for the Øresund trains are not online for 13 April yet. There are also not any commuter trains running all the way from Malmö to Stockholm, that would require more transfers. The direct trains between Malmö and Stockholm are long distance services operated by SJ and Snälltåget.
Øresund trains run between Copenhagen and Malmö every 15 minutes during daytime (unless there are big track works planned that I am not aware of yet), so getting a good transfer should not be a problem at all. Would recommend taking an earlier train, just to be sure you won’t miss the connection in Malmö.
Tickets for commuter trains can be purchased at the stations on the travel day, but as mentioned above I would strongly recommend booking the entire journey on the same ticket through SJ’s website, as your transfers then are protected in case of missed connections due to unforeseen disruptions.