My ds1 is 3.8 and going through a similar fussy phase, after eating pretty much anything for the first 2 years. He would eat sausages/chicken nuggets/chips/mash/beans for every meal if he could.
But we only do one meal most of the time, it's usually stuff that we want to eat too roasts/stews/mexican/curry etc etc. For 2 days of the week Dp works late and those days the dc's do get fish fingers or very simple meals, theres no way I can cook something complicated with 3 of them to contend with.
We don't pander to them really, everything with the meal goes on the plate, if they don't like they don't eat, but nothing else is offered. Some times ds1 will eat nothing of the evening meal, but tbh I'm not bothered, he's obviously not wasting away. We don't engage in yuck or I don't like it conversations, just allow him not to eat it but we do say "big boys eat dinner up/try new things" etc, he's very into being a big boy.
Often they will try, and like the most random of things that you would never guess they would. Dp likes to make soup (which I can't stand bleurgh) but the dc's will lap up onion soup with bread.
Dd went through a similar phase and now at 6 will try anything. I would really really cut out the pandering to her, especially as she has essentially the same meal every night. She is controlling you, it's not a good lesson for her to learn. Cut it out now before it becomes too ingrained.