Run multiple SHELL commands within same SHELL - perl

Question

I am working on a legacy and confined system, where I do not have any known way to get anything installed. Now, I need to run multiple SHELL commands on a same shell. For example, the 2nd command should be aware of any changes done to the SHELL environment by the previous command. (like Environment variable manipulation). The system does not have perl expect module available, so I am trying to use IPC::Open3 to open shell and run commands and checking the stdout and stderr for expected strings. This works fine, for only the first function call of runner function and not the 2nd call.
Here is my code, dumb down version:
#!/usr/bin/perl
use IPC::Open3;
use utf8;
#First expect script
my $pid = open3(*IN, *OUT, *ERR, "/bin/bash");
my #output_arr;
my #error_arr;
sub runner {
my ($PID,$CMD,$REGEX) = #_;
print IN "$CMD\n";
close IN;
waitpid $PID, 0;
my $cmd_output = do { local $/; <OUT> };
my $cmd_error = do { local $/; <ERR> };
if ($cmd_output =~ m/$REGEX/ or $cmd_error =~ m/$REGEX/) {
print "$CMD output contains $REGEX\n"
}
else
{
print "$CMD output does not contain $REGEX, command output is $cmd_output ,error is $cmd_error\n"
}
push #output_arr, $cmd_output;
push #error_arr, $cmd_error;
return ($cmd_output, $cmd_error);
}
# This data will come from other progams.
#this works
my ($date_output, $date_error) = runner($pid, "LC_ALL=C date", qr/2023/s);
#this never works
my ($date_output, $date_error) = runner($pid, "LC_ALL=C date", qr/Jan/s);
The output:
LC_ALL=C date output contains (?^s:2023)
LC_ALL=C date output does not contain (?^s:Jan), command output is ,error is