I finally chose JetBrains Mono as the foundation for the new font design. It features excellent glyphs, metrics and kerning, and provided me with a great reference for learning about marks and anchors, saving me a lot of time.
In this pre-release, I rounded all the glyphs in the font and removed some glyphs and ligatures that uncommon (much "opinioned"). This has taken the project a big step closer to V7.
more details: #27