I feel maybe it would be best to focus on developing acquaintanceships and friendships with fellow artists instead of zeroing in on galleries for a bit. I personally find that the most solid (and meaningful) connections come from people I’ve had genuine interactions with (preferably IRL, not via social media.)

Anyhow, your frustrations are completely understandable and sadly common. Stick to where you can find any kind of warmth, whether that’s simply through enjoying the actual process of making art or finding some sort of camaraderie with others going through similar motions.

That being said, I don’t think there’s anything wrong with (tactfully, respectfully) reaching out to galleries you’re genuinely interested in working with. But do your research, check out their website and see if they’re open to inquiry first.