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Yes, direct swap no modifications necessary. I've put AGM in all my vehicles, oldest being an '84. Your '18, like my '19, does not have a battery monitoring system like the newer trucks. The manual just says to leave the truck undisturbed for at least 8 hours. I imagine you do that every evening anyway.
Here is a thread I made awhile back. Never did make any Forscan changes and do not believe it is necessary. As you will see, others have simply replaced with AGM's, nothing else, and had no problems. https://www.ford-trucks.com/forums/1677378-forscan-agm-battery-setting.html
The Forscan change "Battery_Cfg ENUM: 0=FLD 1=AGM" probably changes the algorithm in the BMS to better charge and maintain the battery type. While leaving it to Flooded Lead Acid would work, it would not be optimal and over time could degrade the batter faster than if set to AGM.