Cannot do a restore using PgAdmin4 after a new install of PostgreSQL - pg_restore.exe file not found
I was able to fix (or patch) the problem by coping files.

Searched for pg_restore.exe from folder 'C:\Program Files\PostgreSQL\13'. I found the file in 'C:\Program Files\PostgreSQL\13\bin'.
Then I copied all the files from 'C:\Program Files\PostgreSQL\13\bin' folder to 'C:\Program Files\PostgreSQL\13\pgAdmin 4\runtime' where the error message says file is missing. Note: After install, there was no runtime folder. I had to create it.
The error went away and restore seems to work. I am not sure this is the right solution, but for now, it works.