Anyone else have a picky pooch?

I have 2½ year old Chihuahua who has always been a picky eater. I've tried several brands and flavors of dog food and she enjoys then for a while but towards the bottom of the (4-5lb) bag she starts to not wat as much.

She will go a day where she barely eats then the next scarfs if all down. I assume it's because she realized she's not getting a different food and gave in to her hunger.

Here's a pic for cuteness ❤️ my sweet baby belle

I can't tell you how many foods I've tried. She acts the same with them all.

Turns her nose at first then loves it then turns her nose toward the end of the bag. I keep her food in an air tight container so it doesn't get stale or anything and a bag will usually last her a month or so.

Any tips / suggestions would be great.

She typically gets a new food every month and it's all been high quality.

She's not like my other dogs who will eat whatever you put in front of them.

She does love getting treats such as banana, strawberries, apples and the occasional peanut butter and bread but those aren't given often and in small small quantities.