Isn't it better not to rely on one wallet with all your wealth? I don't know why many people try to search for a wallet that contains all cryptocurrencies even if it is less secure or less downloads/reviews. Hardware wallets are almost the only option to support most cryptocurrencies and you can use open source hardware wallets, otherwise Unstoppable - Bitcoin & Crypto Wallet is the only available and open source option.
I also used this wallet for some time and in general there were no problems with its use. I am not sure that it is the only wallet with open source code, but in any case it is well developed by the developers and it seemed to me that the updating of the support in the current state also continues normally. But of course all such wallets should not contain any large amounts in cryptocurrency and be used, as they say, for small payments.