Self Custody

Crypto is banned in my country, and I can't access a cold wallet. Instead, I'll use a separate mobile phone that will remain offline 99.99% of the time. I plan to install a secure Bitcoin/Crypto wallet to self-custody my sats away from exchanges. I've looked into Electrum, and it seems like the best option so far (if you know of a better one, please let me know). This is my first time self-custodying Bitcoin, and I have a few questions about how Electrum works. I understand that I'll be using the Lightning Network, but I'm not clear on whether the Bitcoin will stay on the Lightning Network or eventually move to the main Bitcoin blockchain over time. Could you explain how that process works?