Enlisted

This is actually a very easy achievement to get in a custom game. These are the settings I used to finish with 20 captures:

Crossplay: consoles only
Game Mode: Lone Fighters
Difficuly: Standard
Max AI soldiers: 20
Mission: Monastery

I liked monastery because all the points are inside on higher levels making the point easy caps for you and the enemy AI. Just run from point to point capping to your hearts content.

In order to get this achievement, you must first reach level 3 in order to have custom matches available to you.

Next you want to use the following settings:

Game mode: Squads
Difficulty: Standard
Max players: 20
Max AI-soldiers: 12
Team armies: Allies/Axis
Server: Any
Crossplay: Consoles Only

Campaigns: Battle of Berlin
Missions: Monastery

When selecting the missions, you must scroll all the way down until you see Monastery with the word "Conquest" underneath!

Using these settings, I was able to get 11 my first try after struggling to use the other guides! Hope this helps!

This must be done in the "Conquest" mode, there's 3 neutral flags/territories in the map that both teams fight to control, also you can't choose between the Invasion and Conquest modes so you'll have to be lucky.

Best advice i can give is to move on from to point, trying to capture and recapture as many points as you can. Try focusing on points A and C since those are usually less contested and busy than B. You can check how many points you have captured in the scoreboard.

It also helps a lot when the game is evenly matched and both teams are competent enough to keep recapturing points to keep the match going for longer, giving you more time to get the number of captures you need.

Note: There's a chance the achievement might be bugged, in my case i finished the match with only 7 captures and the achievement popped anyway at the end of the match. Before you ask, no, i don't believe it's a description error and the requirement is actually lower since i completed matches earlier with 8 or 9 captures and the achievement didn't unlock then.