Miningcore Setup Guide for Ubuntu

I’m looking for a clear, step-by-step walkthrough that lets an intermediate Ubuntu user (me) bring the very latest Miningcore up on Ubuntu 24.04, fix the “System.NullReferenceException: Object reference not set to an instance of an object” crash I’m hitting on start-up, and add a single coin with three dedicated stratum ports:
• low-diff for CPU/Nerdminer
• mid-diff for Lucky miner or older ASICs
• high-diff for the newest ASICs and big rigs

Here’s what I need:
1. Prerequisites and exact package list, including dotnet, redis, postgres, firewall rules and any kernel tweaks.
2. Git pull / compile instructions for the current Miningcore release, plus the settings that prevent the NullReferenceException.
3. A complete pool.json (or split config) that introduces one coin of your choice, mapped to three ports with proper varDiff or static difficulties to match the hardware tiers above.
4. Systemd service file so the pool starts automatically on reboot.
5. Quick-test commands to confirm the daemon, database and stratum layers are talking.
6. Troubleshooting tips for the most common mis-steps (ports blocked, redis auth, database migrations, coin daemon RPC).

Deliver the guide as a Markdown document and include any sample configs or scripts in a separate zipped folder. When I follow your guide I should be able to: start Miningcore without the exception, see all three ports listening, connect with a miner at each difficulty level, and watch shares roll in.