pooja shah I assume that you've chosen to remain on a weekly Jenkins version that is over 15 months old because you don't want to evaluate new Jenkins versions. That choice will limit your other choices and will significantly complicate the evaluation of those choices.
Git plugin 4.3.0 updated the minimum Jenkins version from 2.138 to 2.204. You may be able to install git plugin 4.2.2. Anything 4.3.0 and later will not operate correctly in Jenkins 2.189.
Git client plugin 3.3.0 updated the minimum Jenkins version from 2.138 to 2.204. Git plugin 4.2.2 requires git client plugin 3.0.0 or newer. It should be able to operate with any git client plugin 3.0.0 through 3.2.1 (inclusive).
Since you're very focused on reducing risk, you should assure that you have reliable backups of your system before you run any of those experiments with plugin versions.
Since you're very focused on reducing risk, you should confirm that you are not affected by any of the Jenkins security advisories published since the release of Jenkins 2.189.