No, sorry, lack of clarity: you said the trial was "supposed" to start in 2018. That's not true, they haven't missed any milestones. The signaling all along has been "we think we're on to something and we're trying line up funding to prove it", and that remains the case.
The goal of the tech is to reduce the subjective experience of tinnitus on a temporary basis. They believe they have demonstrated an effect in animals and a small number of humans which represent some significant minority of the tinnitus population. What the long term effects of continued treatment over months or years is, is not something which has even been speculated about, as far as I know (nor will the Phase-II attempt to solve that). The range of possibilities, then, is probably (from most pessimistic to most optimistic): "this doesn't actually work the way we thought it did, it does nothing"; "this works for some people for a short period of time and then the effect wears off"; "this works for some people over an extended period of time as long as the treatment is continued"; "some people achieve a reduction of tinnitus with long-term therapy which is sustained after cessation of device use".
They're definitely tinkering with some interesting and novel neurological mechanisms, and I think it's pretty reasonable to expect that whatever happens, some useful things about tinnitus will be learned. My own subjective experience was that there did seem to be an effect which was achieved after ~14 days of use, and sustained for 14 days of use and then tapered off within a day or two following discontinuation. However, if this actually turned into a product right off the bat in 2020-2024 which dramatically reduced tinnitus in the long-term in a majority of patients, I'd be somewhat surprised.