When it comes to dairy flavours, milk is the lightest in flavour compounds, though other things like fat, protein, calcium, sugars, and other things contribute significantly to the flavour. When it comes to pure flavour development, this is hard to replicate.
The Dairy Flavours Formula Sheet will help you get started with a milk flavour, using aromatic components. Beyond my formulas, you will find some research information below, including a more detailed milk flavour formula from a research paper. That paper is not publicly available, but there are 5 additional research documents at the end that can help guide you.
As usual, if you have questions, post them below.
Creation and Imitation of Milk Flavour by Guangyong Zhu; Zuobing Xiao (2017)

References
The Flavour of Milk
By John C. Price and Donald J. Manning, National Institute for Research in Dairying (England)
https://img.perfumerflavorist.com/files/base/allured/all/document/2016/04/pf.8314.pdf
Exploration of milk flavor: From the perspective of raw milk, pasteurized milk, and UHT milk Lixiang Lan, Weizhe Wang, Yufang Su, Hongyan Xu, Jiyu Han, Xuelu Chi, Yanmei Xi, Baoguo Sun, Nasi Ai https://pmc.ncbi.nlm.nih.gov/articles/PMC11719328/
Analysis for different flavor compounds in mature milk from human and livestock animals by GC × GC-TOFMS (Food Chemistry: X Volume 19, 30 October 2023)
by Yinggang Sun, Yanzhi Wu, Ben Liu, Rui Chen, Yanjun Qiao, Qiu Zhang, Qian Li, Xiaowei Wang, Zeying Wang https://doi.org/10.1016/j.fochx.2023.100760
Contribution of Milk Fat to the Flavor of Milk
A. TAMSMA, F. E. KURTZ, R. S. BRIGHT, and M. J. PALLANSCH Dairy Products Laboratory, Eastern Utilization Research and Development Division ~ Washington, D.C.
https://www.journalofdairyscience.org/article/S0022-0302(69)86872-4/pdf
Analysis of Flavour Compounds in Milk Flavourings (Scion Instruments)
https://scioninstruments.com/analysis-of-flavour-compounds-in-milk-flavourings/