TL;DR: Bitcoin wallet security is multifaceted and involves hardware, software, storage of seed phrases, and user handling. In general, a multisig wallet using different hardware signing devices and open-source, reproducible software offers the most robust security model. Be mindful that seed phrases are best stored in engraved metal and never entered into a computer to avoid compromise.
Security, particularly concerning Bitcoin wallets, is a complex topic, so there is no simple answer. Generally speaking, a multisig wallet that utilizes multiple hardware signing devices from various manufacturers may be considered the most secure type of Bitcoin wallet. However, the physical features of a Bitcoin wallet constitute only a small part of its overall security. Other factors to consider are the software used, how securely your mnemonic (seed phrase) is stored, and, most importantly, your handling of the wallet.
Wallet software that is open source and provides a reproducible build process is particularly beneficial. This is because such software is likely to be scrutinized by many users, who can then provide feedback to the manufacturer if they discover any bugs or security vulnerabilities. Storing the seed phrases in an engraved metal format is also highly recommended, as is redundantly storing the Xpubs of all individual keys, or the wallet descriptor, in multiple locations when using a multisig wallet.
However, be aware that these security measures are rendered useless if the seed phrases have ever been saved onto a computer. Such seed phrases should be regarded as compromised and never used again. Under no circumstances should a computer be granted access to your seed phrases, whether through typing, copy-pasting, screen sharing, saving them in the file system, or worse, in the cloud.
Some recommended components for a secure wallet setup are:
Hardware devices: BitBox02, Blockstream Jade, ColdCard
Wallet software: Blockstream Green, Electrum, Specter
Seed storage: Seedor, CryptoSteel