I've been a part of the creation of 6 start-to-finish games, with several unfinished projects contributing to my experience as well.
Of these projects, I directed the creative vision for most recent 4 (some not listed here), using Figma for visual communication, and Confluence (for larger) or Google Docs (for smaller) documentation. I try to place on emphasis on solidifying the main story points, primary mechanic, and desired feel first that every team member can be on board with, then dive into the specifics personally, collaborating with relevant team members.
Having experience in 2D art, 3D art, and a computer science background gives me both the skills needed to rapidly prototype for any design work relating to those fields, (Asset lists, level layouts, game mechanics, etc.) and helps me to better understand and communicate with those teams.