auth.log file in bullseye os

I have debian gnu/linux 11 (bullseye), in which the /var/log/auth.log file only contains log of current boot and not any previous boots, I need it to store the logs of previous boot for verifying the activities.

How do I do it?

I actually compared /etc/logrotate.d/syslog-ng of both debian gnu/linux 11 (bullseye) and Debian GNU/Linux 10 (buster) because buster os had logs of an entire week and on comparison both were same.

The code in /etc/logrotate.d/syslog-ng of bullseye os is as below
/var/log/syslog
{
rotate 7
daily
missingok
notifempty
delaycompress
compress
postrotate
invoke-rc.d syslog-ng reload > /dev/null
endscript
}

/var/log/mail.info
/var/log/mail.warn
/var/log/mail.err
/var/log/mail.log
/var/log/daemon.log
/var/log/kern.log
/var/log/auth.log
/var/log/user.log
/var/log/lpr.log
/var/log/cron.log
/var/log/debug
/var/log/messages
/var/log/error
{
rotate 4
weekly
missingok
notifempty
compress
delaycompress
sharedscripts
postrotate
invoke-rc.d syslog-ng reload > /dev/null
endscript
}
and the code of logrotate.conf of bullseye os is
:/etc$ sudo cat logrotate.conf
# see "man logrotate" for details

# global options do not affect preceding include directives

# rotate log files weekly
weekly

# keep 4 weeks worth of backlogs
rotate 4

# create new (empty) log files after rotating old ones
create

# use date as a suffix of the rotated file
#dateext

# uncomment this if you want your log files compressed
#compress

# packages drop log rotation information into this directory
include /etc/logrotate.d

# system-specific logs may also be configured here.