Yeah, I'm researching for alternatives since I started this post and I realized that keeping funds in a lightning wallet and cash-out to cold wallet after reaching x$ threshold will be the most secure thing to do. I'm still searching tho.

turker

bitcoin

Is there any way to use custom domain as BTC wallet address?

What you want is a Paynym which is much not secure and private than a public domain name.

Aside from that, unless your domain name points to a constantly changing BTC address, you'll be creating a lot of future pain when it comes to UTXO management, and potentially doxing yourself.