You will notice the difference in how esports players play this mode. Here the player plays more carefully, picks like in a competitive mode, and changes position carefully. Every good player has their scheme of how to play dm. It can take 15-20 minutes to wake up your arms or longer for a long, complex workout. Even if a professional player plays dm without a specific goal to warm up, his game is not like "run and shoot". During the game, he feels what needs to be done and how to do it, which trains the skill of critical thinking.
You must first understand what types of this game mode exist. FFA DM - the usual dm where everyone kills everyone using everything. That is the most popular type. HSDM - here, the kill is counted only if it hits the enemy's head. PISTOL DM - only pistols are available to you. PISTOL HSDM is a combination of the two types, as mentioned earlier in dm. MULTIDM - here all game modes change one by one. AWPDM - only sniper rifles are available. NOSOUND - dm where everyone has no sound in the game.
It is acceptable if the sound is quieter than the sound in the game. That is detrimental to your workout. You need to immerse yourself in the game and focus; the music will make your workout a simple waste of time and fun.
Only you can know what you need. One person needs to run around the map for 15 minutes and shoot at everyone, the other needs to stand in closed positions for 30 minutes and defend.
One piece of advice will help you - play the way you would play a ranked game mode. Take every death seriously, play it safe, and pretend it's a real game. Simulate real situations. Here, during training, you will encounter many of the moments that occur in a competitive game.
If you entered this mode to warm up, you have to find and diagnose your problem. You need to work out difficult moments and strengthen your weaknesses. That will help you improve your game skills and develop a new understanding of this game. Analyze yourself, and then your training will bring significant progress.
Choose maps you often play to remember the geometry of certain places on the map. So you will use these moments in practice in a real game. Your training should be such that you increase your level of play, which depends on understanding the geometry of the map and the problem areas of this map.