A quick search after seeing the error below shows that you are running an outdated version of CMB2. In this case version 2.6.0 from January 2019. CMB2 2.8 fixes the error being thrown in this plugin when running PHP >= 8.x: #1396.
PHP Deprecated: Required parameter $field_id follows optional parameter $type in
/usr/.../plugins/heartbeat-control/vendor/cmb2/cmb2/includes/rest-api/CMB2_REST.php on line 693
A quick search after seeing the error below shows that you are running an outdated version of CMB2. In this case version 2.6.0 from January 2019. CMB2 2.8 fixes the error being thrown in this plugin when running PHP >= 8.x: #1396.