Open source and closed source have little to do with centralized/decentralized when it comes to making wallet software. It is important to understand that the Bitcoin network and blockchain are decentralized. However, all wallet software is centralized (whether open source or proprietary). Regardless of whether you use the wallet from your personal computer or access it through a web interface or mobile app on a web server, the wallet software is centralized.

Perhaps you meant the terms "custodial" and "non-custodial" wallets? But it has nothing to do with the type of wallet software, because both of them can be either open source or closed source.