I struggled with disordered eating before HRT. A few weeks in, another trans girl explained to me that the body needs energy to do its thing. It's basically second puberty and you know how much teenagers eat.
I was like you, being able to eat a couple of meals and be satisfied. Now, I snack more. I also eat smaller meals as it takes less to fill me up. I'm also ~6 months on E, so I've lost some muscle mass. Despite my new eating habits, I've been able to maintain around 70kg at 180cm tall. Meanwhile, my body's been burning the fat buildup from T and packing it onto my butt, thighs, and chest.
If you want my two cents, try snacking more and just eat when you're hungry. You don't have to eat until you're full, just until you're not uncomfortable anymore. Trust the process and let your body do what it needs to do.
If you start going in a direction you don't like, you can stop. You might also consult your doctor for advice
You fool! Now that I have your auth code, I'm gonna steal all of your internets!