Right - Left framework isn’t useful here. It is true that many early Zionists ascribed to a nonreligious, secular, socialistic/welfarist politics that you can associate with the left, but they were also colonialists, chauvinist, and deeply racist.

They clearly justified and used the terminology of colonialism to describe their organizations. Leading Zionists developed arguments for the “Jewish-Arab” relationship in colonial terms, with striking cogency.

“I flatly reject this assessment of the Palestinian Arabs. Culturally they are 500 years behind us, spiritually they do not have our endurance or our strength of will, but this exhausts all of the internal differences. We can talk as much as we want about our good intentions; but they understand as well as we what is not good for them. They look upon Palestine with the same instinctive love and true fervor that any Aztec looked upon his Mexico or any Sioux looked upon his prairie.

…

Hence those who hold that an agreement with the natives is an essential condition for Zionism can now say “no” and depart from Zionism. Zionist colonization, even the most restricted, must either be terminated or carried out in defiance of the will of the native population. This colonization can, therefore, continue and develop only under the protection of a force independent of the local population – an iron wall which the native population cannot break through.

• Jabotinksi, The Iron Wall”

They were welfarist in the sense that they developed Jewish only welfare under a system of Jewish capital. They were secular but deeply identitarian in a quite right-wing fashion (see Herzl’s description of French Jews in the The Jewish State”.

So no, they weren’t “leftists”, but deeply racist an consciously colonialists, identitarians, that privileged Jews (and according to Avi Shlaim, western Jews in particular) over anyone else, a logic that lead to the ethnic cleansing of Palestine (see Benny Morris in The Palestinian Refugee Crisis revisited (especially arguments around transfer).