In case the Workshop version gives duff textures, the files for both maps are here https://www.dropbox.com/scl/fi/wwa9wb0d8tizzxjhg0s3z/emp_sinking.zip?rlkey=e24nsal6tjl8g3dkvvzto79yv&st=cmjtjwo9&dl=0
with thanks again to CyberKiller for finding the files and also for a note that DropBox links need pasting into the address bar as they don't otherwise work from Steam...
Unzip into the Empires/Empires folder

Two maps in one - the original emp_sinking, somehow working again, and emp_atoll_b2, a version with various bugs fixed by John Shandy - but where the island doesn't sink
Many thanks to CyberKiller for the dump of map files