The real deal-breaker isn't whether wallet is open-source or not (at least for me) but the clear vision of the company that builds that wallet. Ledger is a company with very cynical attitude towards their own customers and they are very money-oriented instead of being a privacy-oriented company.
and they are not consistent with what they said at the beginning. Ledger is sacrificing the privacy of all users with updates that no one really needs.
A clear vision and mission for open-source wallets will be a sign of how they will be in the future.
But if they violate their own mission statement, you can be sure they don't deserve any place with their customers.
At some point, the same applies to Trezor. While they are open-source, it doesn't mean their wallet is secure because their devices suffer from unfixable seed extraction vulnerabilities and at the same time, the problem lies within company too. This company is very pro-government, has partnered with Wasabi and Blockchain Analysis companies.
Trezor is the final choice, but if they are too pro-government it is not impossible that they will eventually do the same thing as Ledger.
As for the vulnerability of their devices, it can probably still be fixed with some further development.
I don't know which Hardware wallet is the best, we can only see the development at this time.
See how Hardware Wallet Companies compete with each other, providing their latest features to embed controversial features.