Adding a new stanza between existing stanzas with Powershell

Question

After doing numerous online searches I have yet to find a way to do this. There are really two parts to my question:

1. How do you add a new stanza between two existing ones?

   If I have the following stanzas in an existing file:

   [Section 1]
   Host=A
   IP=10.10.10.1
   
   [Section 2]
   Host=B
   IP=10.10.10.2
   

   How can I use Powershell to add:

   [Section 3]
   Host=C
   IP=10.10.10.3
   

   between Section 1 and Section 2 to achieve:

   [Section 1]
   Host=A
   IP=10.10.10.1
   
   [Section 3]
   Host=C
   IP=10.10.10.3
   
   [Section 2]
   Host=B
   IP=10.10.10.2
   

2. How do I add a new stanza after the last comment line of an existing file?

   For example if I have:

   #
   # Last change 1/1/2021
   #
   
   [Profile sql]
   Profile=HR
   

   How would I add:

   [Profile postgres]
   Profile=Exec
   

   to achieve:

   #
   # Last change 1/1/2021
   #
   
   [Profile postgres]
   Profile=Exec
   
   [Profile sql]
   Profile=HR
   

   in Powershell?