Is it safe to store Backup Codes and MFA Authentication Code in Custom Fields?

Basically, the question is the title itself.

I have a Premium Bitwarden account which has more than 120 credentials. I have Multi-Factor Authentication enabled for my mail accounts, Bitwarden, and other important sites. All of these websites have provided me Backup/Recovery Codes, and the MFA Authentication Code which generates the codes themselves.

Normally, I would just create a new Hidden Custom Field and add the codes there for safety, but after browsing a few posts in this subreddit, it seems most users recommend not to put all the eggs in a single basket. However, if I can be truthful, I do not have good idea how and where to store the Backup and Authentication Codes.

In Bitwarden, they are there for my ease, but now I'm getting a bit anxious and skeptical to leave them be. For generating the authentication code themselves, I've been using Aegis Authenticator which has been a great help for years. I have also been keeping backup for Aegis.

Please suggest me some ways to help me keep my data secure. Thank you.