Welcome to the forum
I haven’t used trulicity so cant help there I’m afraid, but can we check that the reason you’re going onto this is because metformin and real low carb eating isn’t working? And that it’s an informed choice rather then just being told “do this”?
Sometimes diabetics aren’t told about just how much change cutting down on all carbs can make (an awful lot!) and they progress into more and more meds without giving diet a decent chance or consideration first. All too common to be told avoid sugar and use brown bread and that’s about the limit to the advice. Worse - type 2’s get told to eat carbs at every meal, to have bread and jacket potatoes and porridge! Not surprising it doesn’t work and the diabetes gets worse in time.
It’s all carbs, so that’s bread, rice, pasta, potatoes of any colour or type. Also anything with flour, all grains and cereals. To a lesser extent but still very relevant are beans, pulses lentils etc and most fruit with the exception of berries. As well as getting numbers under control it usually helps shift otherwise stubborn weight that also help improve bloods. It’s sounds and looks pretty odd as it is very different but it works and you get used to it and even prefer it often.