I'd strongly recommend to upgrade your severely outdated Liferay version to a current one if you intend to keep it safe. This will have the side-benefit of upgrading jquery.

Nobody has ever tested the old version you're running with a new version of jQuery. And all the testing/fixing effort that you're facing would be better invested in a server upgrade.

On 6.2 you should be at the patched GA6 level anyway, before you invest any other time. But don't stop there.