Threre are actually the four dimensions we know about, space and time. Time refers to schedule.

The other so called, 5D, 6D, ... are better stated as BIM uses. Anyhow, the frontier is nowadays the augmentation of the virtual counterpart of the construction with links to sensors and active components, the Digital Twin, an extension of the its use in FM.

BIM is a multidimension. In the classic approach, each dimension functions independently, so information about the object has to be obtained several times by different industries at different stages of construction, there are possible incompatibilities of various independent information models. BIM connects dimensions permanently, Information is shared, Information is a connection.

When it first started BIM only had a few stages that has now grown hypothetically to eight as:

https://cadblogbyamit.wordpress.com/2019/12/01/bim-ds-2d-3d-4d-5d-6d-7d-and-8d-and-benefits.

Then there are advocates of vertical integration, as:

https://www.bimthinkspace.com/2008/02/the-bim-episode.html.

Then because industry has been spasmodic in its take up, with some notable and increasing incidences of successes, yet arguably not enough, at 2D, struggling overall to achieve 3D, because of SME training and technology upgrade costs, apathy, and so on, then there has been a call by Casey Rutland and Fiona Moore of UK BIM Alliance to sort of scrap BIM altogether due to this reluctance of take up, although not to scrap entirely, and sort of transmute it into a more assimilable form, as:

https://www.bimthinkspace.com/2008/02/the-bim-episode.html.

Essentially with BIM being a technological, data driven, computerised integrated system, it probably will remain a semi niche market, nothwithstanding previous valid comments about the need for digitisation, twinning, intercommunication, incorporation into systems such as FM and so on, and its widespread use architecturally in CAD design programs such as Reddit, then integrated programming and other functions, then AI, VR, AR, mixed reality and so on, but to discuss the next stage is difficult because of the real stratification of the industry. Sticking to the original model the next feasible stage is 3D, which is what the governments wants amidst sorting out other issues after achieving a widespread take up of 2D,

Best wishes and good luck.

Incorporating AI into BIM.