BUT the critical and fundamental difference is this;
Substance Ontology is basically Philosophical Realism, i.e. it believes there is a thing-in-itself as the ultimate reality that is mind-independent.Advaita Vedānta posits a substance ontology, an ontology which holds that underlying the change and impermanence of empirical reality is an unchanging and permanent absolute reality, like an eternal substance it calls Atman-Brahman.[385]
In its substance ontology, as like other philosophies, there exist a universal, particulars and specific properties and it is the interaction of particulars that create events and processes.[386]
In contrast, Buddhism posits a process ontology, also called as "event ontology".[387][386]
According to the Buddhist thought, particularly after the rise of ancient Mahayana Buddhism scholarship, there is neither empirical nor absolute permanent reality and ontology can be explained as a process.[387][388][note 69] There is a system of relations and interdependent phenomena (pratitya samutpada) in Buddhist ontology, but no stable persistent identities, no eternal universals nor particulars. Thought and memories are mental constructions and fluid processes without a real observer, personal agency or cognizer in Buddhism. In contrast, in Advaita Vedānta, like other schools of Hinduism, the concept of self (atman) is the real on-looker, personal agent and cognizer.[390]
-WIKI
As such, the ultimate reality is the efficient cause of the mind, thus independent from the mind.
If there are no human minds, Brahman the ultimate reality as Absolute and unconditioned will still exists.
Buddhism in contrast is not Substance Ontology thus basically ANTI-Philosophical_Realism.
Buddhism came about in direct counter the Brahman-Atman idea.
There are various school of Buddhism with different philosophies, but the fundamental of Buddhism as intended from Guatama Buddhist should be the same.
Even with advaita-vedanta [emerged to counter the popularity of Buddhism then] which is quite close to Buddhism, there is no change in its fundamental, otherwise advaita-vedanta might as well be recognized as Buddhism.Do Buddhist believe in god?
No, we do not. There are several reasons for this. The Buddha, like modern sociologists and psychologists, believed that religious ideas and especially the god idea have their origin in fear. The Buddha says:https://www.buddhanet.net/ans73.htm
- "Gripped by fear men go to the sacred mountains,
sacred groves, sacred trees and shrines".
Dp 188