The next problem is that whatever tunnels you have are limited in size by your ability to pressurize and heat them. And it would be far preferable if they were horizontal <><>instead of sloping and irregular
We have the off-the-shelf technology, experience, and engineering smarts to overcome all of the obstacles you present.
Utilizing the moon's natural geological features to establish an initial beachhead on the moon, is far more doable (and far less expensive) than mounting a robotic mission of heavy tunnel boring equipment.
Carving out our own tunnels and underground chambers is obviously the preferred permanent habitat solution, but those missions will have to come later, as we build up our manned presence and infrastructure.
Think in gradients. Establishing permanent, robust, lunar bases, is a gigantic endeavor which will take many years to fully put in place. It has to be done in baby steps, one bit at a time, similar to how we established human outposts in Antarctica.
Tunneling robots use existing technology, and can work continuously and semi autonomously. They could be at it for a year or more before people set foot on the Moon.
Literally the only hard part is getting them to the Moon. Once they arrive they need nothing but remote instructions for all that time. Zero risk.