I have done a few upgrades to 22.11.x and 23.05.x now, but I have not seen this error before: 

Upgrade to 22.06.00.084  [21:21:43]: Bug 31162 - Add primary key to erm_eholdings_packages_agreements
ERROR - {UNKNOWN}: DBI Exception: DBD::mysql::db do failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'CONSTRAINT erm_eholdings_packages_agreements_uniq,
                ADD PRIMARY K' at line 3 at /usr/share/koha/lib/C4/Installer.pm line 741

I can find that constraint in two places: 

* 220600079.pl:

        unless ( TableExists('erm_eholdings_packages_agreements') ) {
            $dbh->do(q{
                CREATE TABLE `erm_eholdings_packages_agreements` (
                    `package_id` INT(11) NOT NULL COMMENT 'link to the package',
                    `agreement_id` INT(11) NOT NULL COMMENT 'link to the agreement',
                    UNIQUE KEY `erm_eholdings_packages_agreements_uniq` (`package_id`, `agreement_id`),
                    CONSTRAINT `erm_eholdings_packages_agreements_ibfk_1` FOREIGN KEY (`package_id`) REFERENCES `erm_eholdings_packages` (`package_id`) ON DELETE CASCADE ON UPDATE CASCADE,
                    CONSTRAINT `erm_eholdings_packages_agreements_ibfk_2` FOREIGN KEY (`agreement_id`) REFERENCES `erm_agreements` (`agreement_id`) ON DELETE CASCADE ON UPDATE CASCADE
                ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
            });
            say $out "Added new table 'erm_eholdings_packages_agreements'";
        }

* 220600084.pl:

        unless ( primary_key_exists('erm_eholdings_packages_agreements') ){
            $dbh->do(q{
                ALTER TABLE erm_eholdings_packages_agreements
                DROP FOREIGN KEY erm_eholdings_packages_agreements_ibfk_1,
                DROP FOREIGN KEY erm_eholdings_packages_agreements_ibfk_2,
                DROP CONSTRAINT erm_eholdings_packages_agreements_uniq,
                ADD PRIMARY KEY(`package_id`, `agreement_id`)
            });
            $dbh->do(q{
                ALTER TABLE erm_eholdings_packages_agreements
                ADD CONSTRAINT `erm_eholdings_packages_agreements_ibfk_1` FOREIGN KEY (`package_id`) REFERENCES `erm_eholdings_packages` (`package_id`) ON DELETE CASCADE ON UPDATE CASCADE,
                ADD CONSTRAINT `erm_eholdings_packages_agreements_ibfk_2` FOREIGN KEY (`agreement_id`) REFERENCES `erm_agreements` (`agreement_id`) ON DELETE CASCADE ON UPDATE CASCADE
            });
        }


Database version: MariaDB 5.7.34-0ubuntu0.18.04.1-log

OS: 
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.6 LTS
Release:	20.04
Codename:	focal