Hare Krishna Nuala Mataji. Yes oneness can mean different things according to the teaching and level of understanding. When Mayavadis are speaking about oneness they believe all is one and they are that supreme oneness. Although there are many different philosophies they generally fall into four categories. These four categories are personalism, impersonalism, yoga and voidism. https://krishna.org/the-four-philosophies-impersonalism-yoga-personalism-and-voidism/ . Those who worship God as a person are known as personalists. And Mayavadis are impersonalists. To explain this without putting emphasise on Lord Sri Krishna, we can speak about god as the absolute truth. And the absolute truth has three aspects Brahman, Paramatma and Bhagavan. The Brahman aspect of the absolute truth is known as the impersonal Brahman. It is the all pervading effulgence of the Supreme Lord. And those who become one with this aspect of the absolute truth often seek this without knowledge of the Paramatma and Bhagavan features of the absolute truth. This lack of knowledge is because they have not developed devotion unto the personal feature of the absolute truth, Bhagavan. The Mayavadis have a misconception that the Impersonal Brahman is the highest aspect of the absolute truth and believe they can become one with this thus becoming the Supreme Lord. This however according to His Divine Grace AC Bhaktivedanta Swami Prabhupada and the line of disciplic succession is in fact a misconception of the absolute truth. Those who develop loving devotion (Bhakti) for the supreme lord realize the absolute truth is in fact variegated. This means there is a different quality to the oneness experience by those who have developed Bhakti. This oneness is known as Acintya bhedabheda tattva. The philosophy of simultaneous oneness and difference. This means we are one in quality but not in quantity. The example is often giving that we are like the sparks that emanate from a fire in relation to the supreme. And it is explained we all are unique individuals just like every snowflake is unique. And the goal of Bhakti is to fully awaken our loving relationship with the Supreme Lord. Bhagavad-Gita chapter seven, text twenty four: Unintelligent men, who know Me not, think that I have assumed this form and personality. Due to their small knowledge, they do not know My higher nature, which is changeless and supreme. https://www.asitis.com/7/24.html. I hope this helped to fully answer your query. Haribol. Your Servant, Bhakta David.