Yeah shortly after posting I realized I made a mistake 
Same applies for Bangladesh by the looks of it:
The Government has approved the usage of Deep packet inspection to monitor web traffic.[5] According to Freedom House, Bangladesh is partly free.
Meaning not only DNS is sniffed/filtered but also unencrypted SNI when connecting to web servers:
The desired hostname is not encrypted in the original SNI extension, so an eavesdropper can see which site is being requested.
If you configure unbound with that config file, it will function exactly the same as pihole-FTL does but without the ad blocking.
You can configure Pi-hole with any upstream DNS server IP(s) that you desire exactly the same as if you would with that unbound forward-addr config file but with one less DNS hop.
Check the Custom 1 to 4 address fields in the DNS settings also described in the docs:
With the pihole-FTL daemon you already have a DNS server with many options:
But it doesn resolve DNS names to IP's recursively like unbound can if configured correctly.
Meaning no unwanted config file and below needs to resolve: