Basic PowerShell Script Issue: “Expressions are only allowed as the first element of a pipeline”

Please help me. Trying to use the variable as a value for subsequent processing does not work. I use it like this:

$SourceLog = 'System'
$Begin = "03/06/2021 10:50:54"
$End = "03/06/2021 13:50:54"

$file = "$PSScriptRoot\ignore.txt"
$DB = Get-Content $file

$arr = @(foreach ($Data in $DB) {
    $First, $Second, $Third, $Fourth = $Data -split ',' -replace '^\s*|\s*$'
    $fe="!(`$_.Source` -like '$First' -and `$_.EventID` -eq '$Second')"
    write-output "$fe"
})

$a = $arr -join " -and "
$a="($a)"
$a=write-output 'Where-Object -FilterScript {' "$a" '}'

write-host 1- $a

$request = Get-EventLog -LogName "$SourceLog" -After "$Begin" -Before "$End" | %{ $a } | Select-Object -Property Index,TimeWritten,EventID,Source,Message | Sort-Object -Descending TimeWritten | Sort-Object EventID,Source -Unique
write-output $request | ConvertTo-Json

the $a variable is not exposed. He also tried:

$request = Get-EventLog -LogName "$SourceLog" -After "$Begin" -Before "$End" |  Where-Object -FilterScript { $a } | Select-Object -Property Index,TimeWritten,EventID,Source,Message | Sort-Object -Descending TimeWritten | Sort-Object EventID,Source -Unique

File ignore.txt contains:

Zabbix test event,998
Zabbix test event1,998

create this events:

eventcreate /t ERROR /id 998 /l system /so "Zabbix test event" /d "Test ERROR event 999 log by Zabbix - $(Get-Date -UFormat "%m/%d/%Y - %T")" ; eventcreate /t ERROR /id 998 /l system /so "Zabbix test event1" /d "Test ERROR event 998 log by Zabbix - $(Get-Date -UFormat "%m/%d/%Y - %T")"

In one version, I get a void in the output, with different attempts to open the variable, sometimes I received an error message "Expressions are only allowed as the first element of a pipeline"

I tried to do as in the answer to the article, but it did not work: Basic PowerShell Script Issue: "Expressions are only allowed as the first element of a pipeline"