Remote voting for senators is an easy fix, probably (hopefully) temporary with a very low risk of foreign interference.
Remote voting for the general public is fraught with complexity due to voting being the jurisdiction of the states, as well as rife with opportunity for foreign governments to mess with the results.
I mean, we literally saw hacking attempts from the intelligence services of Russia on election reporting servers in 2016. Enabling remote voting for the general public needs EXTREME vetting before going live.
Not doable for 2020.