Well the key information in that article seems to be:
Tunneling speeds increase over time. The first TBM peaked at 4 meters per week. This increased to 16 meters per week four decades later. By the end of the 19th century, speeds had reached over 30 meters per week. 21st century rock TBMs can excavate over 700 meters per week, while soil tunneling machines can exceed 200 meters per week. Speed generally declines as tunnel size increases.
The current VHB has it at 10m per hour x TL, so at TL10 you're going 100 metres an hour. Musk was promising much greater speeds than the article mentions... The Boring Company website is not as 'information free' as it seems, if you look. Their latest project is supposed to go 1 mile per week, which is 1600 metres per week, but only about 10m per hour - but we're not at TL1 are we?
I suppose if you added a nuclear engine (like a nuclear icebreaker) you could go faster, but if all you have is a 'mole machine' the debris behind you clogs up the tunnel, so you need a vehicle to clear the debris and then a process to shore up the walls, build in things like a flat floor layer, power, lights, etc..
I am doing a chapter on construction (say goodbye to the PWH, but a FTE/hour is essentially the same) only I'm trying to be sane about it and include fun useful stuff like robots and fabricators as options - while keep complexity low. The really low effort basic version is just a more sane and scalable application of the High Guard 'method'. At the moment. All rules are subject to intersection with reality and playability.