Currently, I could not find any open-source wallet that supports a large number of altcoins, tokens, and NFTs. The majority of multi-coin wallets are created by exchanges such as Bitget, OKX, and Binance; however, they are not open-source wallets or maybe I still don't know any of these wallet?
So, in terms of security, if you want a secure wallet with full control, hardware wallets are your best option. Trezor should be the cheapest option with open-source code.
I know unstoppable wallets, but the problem is most of the coins and tokens that I usually use do not support unstoppable wallets, mostly wallets from exchanges like Bitget or OKX wallet.
Unstoppable is a great option, but as far as I know, this wallet does not support most tokens or NFTs, only ERC20 tokens.