He hasn't left the THG project.To clarify, we don't know if he left left. He simply said he's not done anything for the THG project for the least year or so (despite one of the April updates has him claiming that as soon as lockdown ended he'd be working 24/7 to find an investor.)
I just looked at the THG website in the Team Page and then in the Crew Page. Tom's image and his position in the company is still up there. Besides if he had left, it would've been announced on their social media pages.
I wouldn't worry about the lack of updates. It's happened a few times before, and when updates do come they announce they've still been working away, contrary to what a lot of you people out there may think.