I'm an LOTW user and setting up the account in the beginning was tricky to say the least, but I have my certificate(s) and have been a LOTW user for years. I have TQSL on my PC, Raspberry Pi 3 and Mac. Recently I started using a Raspberry Pi for digital modes. I have installed WSJT-X and Fldigi on my RPi3 and am happy to say it works very well. I saw the TQSL application for the Pi, but never did set it up until recently. Prompted to do so, I am happy to find it works right from the package. I used my existing callsign certificate. I made a clip showing how to save the callsign certificate container on a PC and then move it to the RPi3. BTW this process worked on the Mac too.