Thank you. Next, I'd like you to temporarily exclude the EA Javelin/FC 26 directories from Microsoft Defender scanning, then immediately test FC 26. Under Windows Security, go to Virus & threat protection > Manage settings > Exclusions > Add or remove exclusions > Add an exclusion > Folder.
Add: C:\Program Files\EA\AC
Also add your FC 26 install folder:
C:\Program Files\EA Games\EA SPORTS FC 26
Restart your PC and launch FC 26. Test it just once. This is just a test and not something I'd recommend leaving permanently without a reason. Remove the exclusions afterward if nothing changes.
You should also check the digital signatures of these files:
C:\Program Files\EA Games\EA SPORTS FC 26\EAAntiCheat.GameServiceLauncher.exe
C:\Program Files\EA Games\EA SPORTS FC 26\EAAntiCheat.GameServiceLauncher.dll
Right-click > Properties > Digital Signatures > Details. You should see: This digital signature is OK.
Let me know what happens.