Since in the meantime Dave has also made a YT video on HNT mining, here are just a few thoughts from me, for anyone wondering it is also worth getting into it. (tl;dr imho rather not)
Ordering the hardware and getting it delivered can take weeks or months. Some manufacturers give the delivery as Feb. 2022. The situation was already like this when I looked at it a few months ago and will probably stay like this until bear market is, HNT smears for other reasons or they succeed and enough coverage stands.
One topic that goes under the radar in many videos is the tax treatment. Now I'm certainly not one to stand up and be in favor of lining Olaf's pockets. Depending on the severity, the state has 5 - 10 years to get you on the scent, before statute of limitations occurs. My understanding is that the income from mining must be taxed above the exemption amount at the personal tax rate. That means the RoI is already significantly higher than it is suggested with (cost router / average revenue per day).
As in any gold rush, there are some who get rich shoveling gold and others who sell the shovels. Whether the network will be a success in the long run, no idea. Whether you get rich with the shoveling? I suspect not.
Bonus: Funny pictures of Chain's problems, just the last few days.