The best practice is that the device private key should never leave the device. One device, one key. A device is lost or compromised? Remove that device’s key from your list.

I also use ConnectBot and importing a private key generated elsewhere never worked for me, so I generate directly in ConnectBot itself and add its public key to my server, which is what I should do anyway.

Install termux [edit: grab from f-droid or their website, their play store version has been out of date for some time and repos likely wont work on it] on your phone and run pkg install x11-repo followed by pkg install putty-tools which should put a copy of puttygen on your phone. Open your file manager and “Termux” should appear like a USB drive (in Google files it’s under “other storage” at the bottom of the home screen), copy your key file there and Termux will be able to access it. puttygen keyfile.ppk -O private-openssh -o id_rsa Should let you convert to OpenSSH format and connect to trusted computers. You can also install OpenSSH in Termux to use it as an ssh client

It also looks like you can install putty in Termux as well, if that’s more convenient for you

nvm, it needs an x11 server, you’re likely better off with the aforementioned method