Powershell scripting replace of variable value within text file like tnsnames.ora where the text for replace is unknown

I'm trying to write into my powershell script the ability to insert a hostname into a file like tnsnames.ora.

The file I am working with has a default value in that field, and I can't rely on what that value will be, so a simple replace of that text string won't work.

I need to be able to check the file for instances of "HOST = abcdefg123" (where abcdefg123 is the server's name place holder) and replace that string with my server's hostname.

The trick seems to be taking this file and locating abcdefg123 so that I can replace it. It can appear multiple times in the file, and the HOST variable may not be the first item on the line.

Here is a sample tnanames.ora file for a SAP database:

A01.WORLD=   (DESCRIPTION =
    (SDU = 32768)
    (ADDRESS_LIST =
        (ADDRESS =
          (COMMUNITY = SAP.WORLD)
          (PROTOCOL = TCP)
          (HOST = columbus)
          (PORT = 1529)
       )
    (CONNECT_DATA =
       (SID = A01)
       (GLOBAL_NAME = A01.WORLD)
    )   )

TEC.WORLD=   (DESCRIPTION =
    (ADDRESS_LIST =
        (ADDRESS =
          (COMMUNITY = TEC.WORLD)
          (PROTOCOL = TCP)
          (HOST = columbus)
          (PORT = 1521)
        )
    )
    (CONNECT_DATA =
       (SID = TEC)
        (GLOBAL_NAME = TEC.WORLD)
        ) )

I was trying to work to adapt the following code (I found in another post) to work but have not been successful so far:

Get-Content file.txt | Where-Object {$_.length -gt 0} | Where-Object {!$_.StartsWith("#")} | ForEach-Object {
   
    $var = $_.Split('=',2).Trim()
    New-Variable -Scope Script -Name $var[0] -Value $var[1]
    
}

The Split by = character would not work right especially where I found there was more than one = argument on the same line (the quoted sample does not show this but the file I was working with does). (Obviously I corrected for the file name. I also tried addition where-object elements to eliminage lines starting with ')' for example, but I don't think that was very useful.