thank you,
ok, so the only workaround to hide the Features in the "Feature Access" menu of extensions is to remove the "Feature Access" for all extensions:
System -> System Options -> Option 5 -> "PT Feature Access" -> No 1 to No. 8 to none.
yes, it works hiding list of all extensions in EXT Directory with Tenant-based Extension Directory display.
3.Group -> 2.User Group -> Tenant
6.Feature -> 6.Tenat -> Extension Directoy -> Tenant