Please follow the advice in the below 2 links:
- sql - In PgAdmin 4 Utility not found - Stack Overflow
- pgadmin 4 - Cannot do a restore using PgAdmin4 after a new install of PostgreSQL - pg_restore.exe file not found - Database Administrators Stack Exchange
Also sometimes some configuration issues also comes up in new installation of pgadmin4 which you can solve by restarting the app.