It’s been discussed many times over the years and was written off by Roon, I think mainly down to Linux having so many different windows managers and not one simple front end to develop for. But in this day and age it does seem a little old fashioned as many apps I use day in day out on Linux work on many distros and windows managers. There is a community remote project that @Jan_Koudijs is working on that’s filling the gap albeit within the limitations of Roons API. Maybe under Harman they might now be pushed to come up with an official Linux client. But I would not hold your breath.
Very long thread on it here