Maybe it is the firewall. The logs /var/log/apache2/error.log look like that:
[Wed Apr 13 06:25:01.430562 2022] [mpm_prefork:notice] [pid 106026] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Wed Apr 13 06:25:01.430575 2022] [core:notice] [pid 106026] AH00094: Command line: '/usr/sbin/apache2'
[Wed Apr 13 06:58:15.017856 2022] [mpm_prefork:notice] [pid 106026] AH00171: Graceful restart requested, doing restart
[Wed Apr 13 06:58:15.053405 2022] [mpm_prefork:notice] [pid 106026] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Wed Apr 13 06:58:15.053416 2022] [core:notice] [pid 106026] AH00094: Command line: '/usr/sbin/apache2'
[Wed Apr 13 06:59:50.079824 2022] [mpm_prefork:notice] [pid 106026] AH00171: Graceful restart requested, doing restart
[Wed Apr 13 06:59:50.109109 2022] [mpm_prefork:notice] [pid 106026] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Wed Apr 13 06:59:50.109121 2022] [core:notice] [pid 106026] AH00094: Command line: '/usr/sbin/apache2'
[Wed Apr 13 07:07:54.550139 2022] [mpm_prefork:notice] [pid 106026] AH00169: caught SIGTERM, shutting down
[Wed Apr 13 07:08:11.230219 2022] [mpm_prefork:notice] [pid 1292] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Wed Apr 13 07:08:11.232310 2022] [core:notice] [pid 1292] AH00094: Command line: '/usr/sbin/apache2'
[Wed Apr 13 07:08:39.156816 2022] [mpm_prefork:notice] [pid 1292] AH00171: Graceful restart requested, doing restart
[Wed Apr 13 07:08:39.270117 2022] [mpm_prefork:notice] [pid 1292] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Wed Apr 13 07:08:39.270129 2022] [core:notice] [pid 1292] AH00094: Command line: '/usr/sbin/apache2'
[Wed Apr 13 07:10:14.106822 2022] [mpm_prefork:notice] [pid 1292] AH00171: Graceful restart requested, doing restart
[Wed Apr 13 07:10:14.133349 2022] [mpm_prefork:notice] [pid 1292] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Wed Apr 13 07:10:14.133360 2022] [core:notice] [pid 1292] AH00094: Command line: '/usr/sbin/apache2'
[Thu Apr 14 11:28:57.120620 2022] [mpm_prefork:notice] [pid 1308] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Thu Apr 14 11:28:57.123634 2022] [core:notice] [pid 1308] AH00094: Command line: '/usr/sbin/apache2'
[Thu Apr 14 11:30:00.137235 2022] [mpm_prefork:notice] [pid 1308] AH00171: Graceful restart requested, doing restart
[Thu Apr 14 11:30:00.173431 2022] [mpm_prefork:notice] [pid 1308] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Thu Apr 14 11:30:00.173444 2022] [core:notice] [pid 1308] AH00094: Command line: '/usr/sbin/apache2'
[Thu Apr 14 11:31:35.468925 2022] [mpm_prefork:notice] [pid 1308] AH00171: Graceful restart requested, doing restart
[Thu Apr 14 11:31:35.506033 2022] [mpm_prefork:notice] [pid 1308] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Thu Apr 14 11:31:35.506046 2022] [core:notice] [pid 1308] AH00094: Command line: '/usr/sbin/apache2'
[Thu Apr 14 12:47:33.596834 2022] [mpm_prefork:notice] [pid 1308] AH00171: Graceful restart requested, doing restart
[Thu Apr 14 12:47:33.637631 2022] [mpm_prefork:notice] [pid 1308] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Thu Apr 14 12:47:33.637643 2022] [core:notice] [pid 1308] AH00094: Command line: '/usr/sbin/apache2'
[Thu Apr 14 12:49:08.528482 2022] [mpm_prefork:notice] [pid 1308] AH00171: Graceful restart requested, doing restart
[Thu Apr 14 12:49:08.563343 2022] [mpm_prefork:notice] [pid 1308] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Thu Apr 14 12:49:08.563354 2022] [core:notice] [pid 1308] AH00094: Command line: '/usr/sbin/apache2'