So I am debating what wallet to get I don't want anything flashy like the nano X etc just holding 2 coins btc and xmr ( monero )

So i am down to either picking ledger nano S or coldcard but I need a reliable safe place to store it I know ledger has a name but it isn't open source right so anything can happen in the future if btc goes up in price and who knows if the card is backdoor idk i just want a reliable safe place to store these two cryptos any suggestions?

also is it true the nano S can be use also not just from your computer but I can pay on the go with the OTG cables and connect it to my phone with the ledger live app?