I'm on an iphone and do you have any app suggestions for iOS devices since I don't see KeePassXC for iOS or Android?
I just went through KeePassXC website and it's not supported on mobile. KeePass, Padloc and Passbolt are open sourced password managers that are available on mobile versions. You can use them to save your passwords but I wouldn't advise you to save your seed phrase or private keys on them. For maximum security, anything seed phrase or private keys should be kept offline.
Also, I just visited KeePassXC's website, they don't have a mobile version but they directly recommend apps for 2 popular phone operating systems. Strongbox and KeePassium for iOS, KeePassDX and KeePass2Android for Android operating system. I haven't tried these apps yet but it's worth a try. But even if they are open source and secure, we should never store important things like private keys there. As for the seed phrase and private key, there is no safer way to store them than keeping them offline at all times.