I use a (cheap and with an open source OS easily fixed during travel) linux laptop for travelling with a small portable USB storage device that I can disconnect, copy, etc..The idea is to have a portable, easily updated linux device that I can carry in my walett without having to worry about my laptop being hacked or stolen from my travel lodging.
To this effect, portable linux of all Proton aps would be a tremendous help, as being portable and even being put in an encrypted "credible denial" hidden file in the USB portable device so that even if the portable usb device is stolen or confiscated, there would be credible deniability about having such accounts with Proton..not so far fetched these days when border authorities are known to force travelers to open their accounts for inspection.
Standard Notes is the only Proton app that is offering, to my knowledge, a Linux appimage. This is extremely useful for the reasons given above and I wish this would be extended to all other great Proton apps !