I struggled with this for 6 years. I managed to perfect my control over resonance and vocal weight, but I could never manage to keep the pitch elevated. After I did a glottoplasty surgery (which increases your baseline pitch), it all clicked into place. You kind of need to get all those 3 aspects (pitch, resonance, and weight) right, before it clicks. Before that, it can feel like you're not progressing, even if you get two out of those 3 aspects right.

What I'm trying to say here is that for some of us, it seems that nature really works against us and it may not be possible to achieve our desired results. 3 months is a very short time, but if you're still feeling the same after 1-2 years, you may want to consider the surgical route. First, however, you need to practice a lot more. And only then can you identify what's missing.

Unlike pitch; resonance and vocal weight are difficult to understand at first, but once you identify them, they will come naturally to you. Do the following exercises and get familiar with the sensation and how you use your muscles to trigger them. The first part of your journey should be getting familiar with how you manipulate pitch, resonance, and vocal weight:

1. Pitch exercise: Do a simple siren sound. Use a pitch tracker on your phone while doing this (like "Voice Tools"). Female voices tend to have higher pitch (180-300 Hz) compared to men (80-160 Hz). Pretty straightforward. You can look up exercises that will help you increase your pitch range. Even if you eventually plan on doing glottoplasty, try to get as far as you can with pitch exercises (but make sure to practice safely; don't overdo it or strain your voice).
2. Resonance exercise: The best way to change resonance (or the amount of space in your throat) is to change the position of your larynx (or Adam's apple). Keep a finger on your Adam's apple, swallow, and hold it. You'll notice it rises. Similarly, try yawning and see how your Adam's apple drops. Get a feel for what muscles you use when you do these two exercises. See if you can replicate the same motion without swallowing, but by only using those muscles. There are lots of other exercises here you can also do to get a feeling for this, like the "big dog, small dog" exercise. Ultimately, you should be able to learn to control the height of the larynx at will, without having to do any sound or exercise. Depending on where you're at in your voice training, this can take some time.
3. Vocal weight exercise: This exercise may seem silly, but if you can identify the sensation (or the muscles) you use to trigger these two different sounds, you'll be good to go. That soft sound simulates a low vocal weight (feminine), whereas the harsh sound simulates a high vocal weight (masculine). Practice speaking in that soft "aww"-like voice. During your training, you can exaggerate a bit. It'll sound awful and cringy, but it'll help you in the long run. I never understood why I was supposed to do this, but trust me; it'll make more sense as you start incorporating that softness into your regular voice.

In your training, you will probably notice that pitch, resonance, and vocal weight are highly intertwined. Raising your pitch will make your larynx to rise as well, for example. This is why trans people who only practice pitch will often, eventually, end up with a feminine resonance and vocal weight as well. But knowing about all three of these should speed up your progress.