Why does my homemade bread always seem to be dense and heavy, despite following a recipe to the letter?

I totally feel you, I've been there too when I first started baking bread. It's frustrating when you follow a recipe to the letter and still don't get the results you want. One thing that might be worth looking into is your mixing technique - overmixing can definitely lead to dense bread. When I'm mixing my dough, I try to just combine the ingredients until they come together in a shaggy mass, then let the dough rest for a bit before kneading. This helps develop the gluten in the dough without overdoing it.

I've also found that the temperature and humidity in my kitchen can affect how my bread turns out. If it's too cold or dry, the yeast might not be activating properly, which can lead to a dense loaf. You might try using a thermometer to check the temperature of your kitchen, and see if that's affecting your yeast. Additionally, you could try creating a warmer, more humid environment for your dough to rise - I like to cover my bowl with plastic wrap and let it rise in a warm spot, like near a radiator or on top of the fridge.

As for the type of flour you're using, all-purpose flour can work just fine for bread, but bread flour does have a higher protein content that can help create a lighter, airier crumb. That being said, I don't think the type of flour is the main issue here - it's more likely something to do with the way the dough is being mixed and risen. If you're willing, you could try experimenting with a few different variables - like mixing technique, temperature, and rising time - and see what works best for you.

Don't get discouraged, though - it takes time and practice to get the hang of baking bread, and it's totally normal to have some trial and error along the way. I'm sure you'll get there eventually, and when you do, it'll be totally worth it - there's nothing like the satisfaction of biting into a warm, freshly baked loaf of bread that you made yourself. Keep at it, and I hope you'll be enjoying light and fluffy homemade bread in no time!