I am very interested, what is this way?
I could move funds from my 1 XLM blockchain(dot)com custodial wallet to a new non custodial wallet (even if I don't know how to open it at the moment) and forget about the new wallet.
You might want to look around about Merge Account. Within the Stellar system, there is an Account merge operation which could do the job, you can learn more at
https://developers.stellar.org/docs/fundamentals-and-concepts/list-of-operations#account-merge. It requires manual intervention to execute the operations. Surely not an easy way to execute the operation for some people who lack technical skills.
Fortunately, someone create an easy way how to execute the operation. You can refer to
https://stellar.expert/demolisher/public. As a caveat, DYOR and DWYOR.
Seriously guys for 1 xlm will you do all of that hassle? But 1 xlm is only 0.11 usd at the moment lol. It's not worth the time and effort. If only this is 1 btc then I think I will also volunteer on moving it into a new wallet. For now why can we just focus on the main concern of the OP and that is by closing his blockchain account.
This one is a strange case because normally any wallet can just close the account of someone who request it and they can also close someone's account automatically if they did something suspicious. I know on some wallets there is an option to delete your account manually. Does blockchain don't have that option? Maybe you can try looking at it at the settings OP.