The Eastern spiritualities and philosophies has gone into great depths on this issue since thousands of years ago and had continuously improve on them to the present.
The first thing is one need to understand the natural inclination to the idea “I” and “All there is” are ultimately illusory. Note Kant’s there is no “I-in-itself” “Universe-in-itself” which the same with the non-theistic principles of Buddhism and the likes.
It is when one clings [naturally driven] to the “I” and “All there is” or “whatever there is” that a terrible angst is generated that drive one’s to seek psychological security and the easy solution is the idea of a God [the all powerful] as a panacea.
The question is how to deal with this angst without clinging to anything. This is how Buddhism came up with the concept of ‘nothingness’ ‘emptiness’ ‘dependent origination’ where there is no dualistic reality but rather the focus is on emergence of reality with the self [as non-self] in engagement with the flow.
Eastern philosophies often come up with seemingly parodoxical ideas, e.g.
‘Action without Action’
‘Fighting without fighting’
They are not contradictions but they have to be viewed in different senses alternating within different time in nano-seconds.
Besides theories based on real collective experiences, Buddhism and the likes focus critically to change the brain and mind via effective spiritual practices. The effectiveness of such practices is evident from the tons of research done on this subject.
The limitation is whilst these Eastern practices has benefits the more effective ones are limited to a small percentage of practitioners. So the solution is to make these philosophies and practices more accessible and practical for the masses without the religious attachments. I am optimistic this can be done with the potential of the exponential expansion of knowledge and information technology.