The project is already dead. Dude hoped he could attract a team of people to work on this project with him, but no volunteers came forth, so he canceled it.
Also, calling this "Project Tamriel" is fucking insulting, because there already is a Project Tamriel: a huge, high-quality mod project for Morrowind with the aim of recreating all of Tamriel in the Morrowind engine, with every province being true to the old lore. They already have a small part of Skyrim released and this year will release the first part of Cyrodiil. It's gonna take many more years (at least a decade, and that's optimistic) before even those two provinces are fully finished, and then there's still High Rock, Hammerfell, Valenwood, Elsweyr, Black Marsh, and Summerset Isle.
Project Tamriel is a sister project to Tamriel Rebuilt, a mod working on recreating the mainland of Morrowind (as the vanilla game only portrays Vvardenfell, the province's central island). TR has been in development for twenty years now. The early years were plagued by inefficiency and modder drama, but by the late 00s they got their shit together and put out their first release. In the last couple years they've improved their organizational skills and workflow, and now they're actually making steady progress with new high quality updates almost every year. They're even overhauling the areas of their early releases, whose quality is noticeably more amateurish compared to their recent stuff.
At the current pace, they might even be able to finish the entire Morrowind mainland, including a comprehensive overhaul of their old material, by 2030. The Cyrodiil team has been at it for about a decade now, and are finally ready to release the western coast of the province as their first release. The Skyrim team is making steady progress, and they've started working on High Rock now, too - for now just the eastern border with Skyrim, but they'll eventually expand the province westward.
It's a long, slow, work-intensive process, especially since the TR/PT teams are incredibly elitist and perfectionist. Their content quality is at least on par with vanilla Morrowind, and in many cases far superior.
But even for a less autistically lore-accurate mod, the amount of work required is staggering simply due to the scale of Tamriel. A mod project that wants to recreate the entire continent - or, worse, the entire planet - would take several decades of work to be done.
Considering Starfield's lack of popularity, it's not at all surprising that nobody with talent is willing to join a project like this. Their time and effort would be better used joining Tamriel Rebuilt, or even Beyond Skyrim, both of which are projects already far into development and with a proven track record of actually being able to release things. This guy's Starfield mod has nothing to show other than over-ambitious plans only a madman would commit to.