HOW TO INSTALL THE FACEPACK
This involves a bit of work, so you'll still need to be patient, but finally, there is a way to replace those images.
1) Unzip Regen UID Finder
2) Place folder in Sports Interactive/FM21/graphics/faces (Mac = HD/users/user/Library/application support/sports interactive/fm2021/graphics)
3) Then in the game go to Preferences > Interface and untick "Use caching" and tick "Reload skin when confirming" – Apply
4) Take a look at your Inbox and see if you have any messages from your Press Officer & Personal Assistant or search for any other staff whose face you want to replace - hopefully, they now have a black image with a number and make a note of this number – PLEASE NOTE there may be several entries using the same image depending on the size of the database you have loaded.
5) Rename your chosen images as the regen numbers you found in 4), create a folder called "A" and place these faces in there. This is so that FM can read the staff faces first before it reads any other regen face packs you have.
1) Unzip fmXML_v0.3.zip
2) Install the program and run, the program is clean & can be trusted.
3) Click Browse and locate the "A" folder you created in STEP 1
4) Under Action, select “Make config.xml file”
5) Under Object, select “faces”
6) Tick “All filenames are IDs” under Options
7) Hit GO! and wallah, you're done.
Now make sure the Regen UID Finder folder from STEP 1 is removed for your FM graphics folder and that you have placed the "A" folder with the staff faces into your graphics folder.
Clear cache and reload the screen!!
As you can tell from the above - this is a bit tricky, so it's one for the die-hard gfx mod fans, but hope this helps.
Big thanks to FMfan.ru and Rowan from Sortitoutsi for the previous work done.