I have a two DC, aged 4 and 2. Currently the 2yo is not a pleasure at mealtimes. I recall the older one being very similar at this age. At one point the sole vegetables the older one would eat were sweet corn and cucumber (when previously had eaten a decent range). The younger DC actually has a broader palate but essentially loves bland carbs and will happily gorge on these. Also has zero interest in sitting still to eat, can escape from the high chair straps, refuses the booster seat and runs off from the toddler table.
What I have learned so far is:
It's just a phase (I know, such a cliche). The older DC went through all this and to top it all I was pregnant and knackered. I caved and did dinner on the sofa in front of the tv. By the time the younger DC was ready to wean we were all back at the table and eating properly. The sofa / tv scenario was relatively short lived and resulted in happier meal times and more food being eaten. It worked and I was less stressed.
I stopped offering food that got wasted and did a lot more simple meals - easy pasta, toast and eggs, jacket potato and beans etc. If we had something more interesting I saved a small bit and offered it. If it was rejected the never mind, I wasn't slaving over something for them. If it got eaten, woohoo! I still follow this mantra and 80-90% of my children's dinners are "safe" food they like, and every now and again I try something new. I also don't allow myself to give a shit if it doesn't get eaten.
Lastly, I can't speak for others, but growing up in the 80s, pasta or curry was exotic! I think most our meals were served with bread or potato or maybe rice. We didn't get blueberries or mango or whatever. I'm sure our parents weren't worrying if our diets were too boring. So the fact my oldest DC went from adoring Thai green curry to rejecting anything with a hint of flavour seems silly to get worked up about - I'm sure it will improve with age, and in fact, it already is.
So my advice is - ride it out, take a balanced view, don't expect too much - offer a balanced diet so you know you're doing your best, but it doesn't have to be exciting or novel, or extensive for now!
For reference, 2yo main foods are easy meals like jacket potato, pasta in various sauces, quesadilla, rice with chicken or meatballs. Nothing fragranced, saucy or spicy. Lunch is snack based eg breadsticks, crudités, sometimes soup (love soup - a great way to get lots of nutrients!).