The FIFA 20 4-1-2-1-2 formation is usually a variation with the standard 4-4-2, and you'll find two versions of this formation. In both versions, the back 4, central defensive midfielder, the central attacking midfielder plus the two strikers stay precisely the same. The principle difference could be the part of the two further midfielders. In one particular variation, they play as wide midfielders and in the other, as central midfielders. This slight difference in positions includes a significant impact around the roles in the other players, along with the team's all-round style of play.

FIFA Expert's recommended work rates and player instructions:
 

Right Back – Medium Attacking / High Defensive
Left Back – Medium Attacking / High Defensive
Right CB – Low Attacking / High Defensive
Left CB – Low Attacking / High Defensive
CDM – Low Attacking / High Defensive
Right CM – High Attacking / High Defensive
Left CM – High Attacking / High Defensive
CAM – High Attacking / Low Defensive
Right Striker – High Attacking / Low Defensive
Left Striker - High Attacking / Low Defensive

FIFA Expert's recommended (4-1-2-1-2 Narrow) player instructions:
Right Back – Stay back while attacking, Normal interceptions.
Left Back – Stay back while attacking, Normal interceptions.
Right CB – Stay back while attacking, Normal interceptions.
Left CB – Stay back while attacking, Normal interceptions.
CDM – Cut passing lanes, Stay back while attacking, Normal interceptions
Right C Mid – Balanced attack, Balanced crossing runs, Normal interceptions, Free form.
Left C Mid – Balanced attack, Balanced crossing runs, Normal interceptions, Free form.
CAM – Stay forward, Get into the box, Free form.
Right Striker – Basic defence support, Drift Wide, Get in behind
Left Striker – Basic defence support, Drift Wide, Get in behind

Strengths: This is, as we discussed earlier on, the most balanced formation in the game and gives you a little bit of everything. Not as popular as it once was (especially on FUT) but still definitely one of the most famous formations. Its strength lies in great passing options. Even on the diagram above, you can see that all the pitch is covered with little gaps around each player. The tight diamond in midfield means that if you're running with this set-up against a team with 3 in midfield, you can dominate that area.

Weaknesses: A weakness for this formation is obviously, the lack of width because of that tight midfield quadrant. Playing against a 4-4-2 or the 4-2-3-1 and you're running the risk of leaving plenty of space for opposition wide players. You need strong full backs because they may be outnumbered on numerous occasions if you don't play this formation correctly.

Key player/position: The CDM is crucial to provide cover, and someone with high stamina and pace like a Kante type player is vital to add a bit more cover for when you don't have the ball. The CAM is the opposite, and they must be central to all attacking moves, so the emphasis on them being an active player in your team is again, vital. 

Most suited style of play: Balanced, slow, possession playsuits this formation best