A version of the below with screenshots is available on the sortitoutsi forums: https://sortitoutsi.net/content/74677/fm26-real-name-fix-placeholder-thread

Step 1:

Go to: 

(for PC Steam users)
Program Files (x86)\Steam\SteamApps\common\Football Manager 26\shared\data\database\db\2600

[\Program Files (x86)\ could be \Program Files\ depending on your set up.]

(for PC Epic Games users)
Program Files\Epic Games\FootballManager26\shared\data\database\db\2600

(for Mac users)
/ Users / username / Library / Application Support / Steam / steamapps / common / Football Manager 26 / fm.app / Contents / Plugins / game_plugin.bundle / Contents / Resources / shared / data / database / db / 2600 

You have to click ,,show packaged contents'' on the fm.app and game_plugin.bundle






Step 2: 

Delete the dbc, edt and lnc folders from the folders above, but leave the 2600_fm folder alone. I repeat, you must DELETE the dbc, edt and lnc folders. Replacing/merging won't see all the changes implemented





Step 3: 

Copy the dbc, edt and lnc folders from this download into the folders mentioned in step 1.