Unpopular Opinion:

You don’t need fancy HW with state of the art with randomized algorithmed that uses a sensor for entropy.

All you need is a pen, paper, a few dices and Knowledge. Here are the high level steps.

1- use an old smart phone/ tablet

2- install Blue Wallet or Electrum Wallet (Wifi or side load)

3- get your device offline (erase network)

4- roll some dices and come up with the 12 words seed phrase.

5- try the seed phrase in Electrum. The 12th word will most probably not checksum. From the BIP-39 word list, go to your 12th word and try the 8 words before or 8 after (for the 12 word seed phrase you have a probability of 1/16 chances to guess it)

6- Once you found the 12th word, add a pass phrase to seal the deal.

7- Export Masterkey for read only application on another device.

8- Sign the transactions generated by the read only device using your offline/air gap phone.

I can do a detailed tutorial with a template I have created to calculate the words by hand if anyone cares…