My belief that Israel is an apartheid state is based on a wide variety of sources - see below:
In 2020 Yesh Din and in 2021 B'Tselem issued separate reports which concluded that the bar had been met for labeling Israel an apartheid state.
Yesh Din report 'The Israeli Occupation of the West Bank and the Crime of Apartheid:
B'Tselem report 'A regime of Jewish supremacy from the Jordan River to the Mediterranean Sea: This is apartheid'
Then in April 2021 Human Rights Watch issued a report,' A Threshold Crossed
Israeli Authorities and the Crimes of Apartheid and Persecution'
This was followed in 2022 by Amnesty International's report,' Israel’s apartheid against Palestinians: Cruel system of domination and crime against humanity'
During 2022 several senior UN officials declared Israel to be an apartheid state. A good example would be Canadian professor Michael Lynk who was appointed to the UN Human Rights Council and in March 2022 stated: "enshrined a system of domination by Israelis over Palestinians that could no longer be explained as the unintended consequence of a temporary occupation."
I would also refer you to the work of Jewish academics such as Dr. Norman Finkelstein and Professor Noam Chomsky who also take the same view.
Besides this, I have spoken to Palestinians living in Israel who have described first hand the daily discrimination they face.