I understand your use case better now. You want to create a Bitcoin wallet using a manually generated seed, which you'll enter into Bitcoin Core on an offline machine, and then use the XPUB to create a "watch-only" wallet on an online machine. This approach can enhance security.

Here's a high-level overview of the process:

Generate Seed: Manually generate a 99-digit base-6 number using dice throws, ensuring it's highly random.
Offline Machine:
Install Bitcoin Core on an offline machine.
Enter the seed to create a wallet.
Note down the XPUB (extended public key).
Online Machine:
Install Bitcoin Core on an online machine.
Import the XPUB from the offline wallet as a "watch-only" wallet.
Create new receiving addresses on the online machine for transactions and PSBTs.
You can follow these steps manually within the Bitcoin Core GUI, which is designed to handle these tasks securely. No additional scripts should be necessary for this process, as Bitcoin Core provides the needed functionality for generating and importing wallets.

Remember to keep your offline machine entirely disconnected from the internet during the initial setup to maintain security. Additionally, ensure you have backups of your seed in case of data loss or hardware failure.