My bread is coming out dense and not rising enough ( The second rising. )

You missed the entire point. The bread is rising fine on the first rise. It is going flat on the second rise. All of your comments reflect the first rise.

Hi! :)

I made a tutorial recently to make homemade bread (you can eat it with sweet food as well as any kind of meal), and I use different method to make bread rise:
https://www.youtube.com/watch?v=0AQR84v__l4&t=177s

I hope it can help you! :)

I have to agree with the slow rise technique. I know, I know, it's so appealing to have bread in 3 hours or less, but what you lose in time, you gain in flavor and texture. Use cool water, let it rise at room temp--during the winter, your bread will take longer to rise. In the summer, it will rise more quickly. But so long as your yeast is good, your bread will rise. I also think that a lot of bread recipes call for too much yeast--2 1/4 teaspoons (1 pack) is plenty for 2 loaves. In fact, I prefer to cut the amount of yeast in most recipes and just content myself with a longer rise.

Any chance you didn't knead it enough before the first rise? Or overkneaded it on the 2nd?

I'm a baker and a lot of what I read above and below is myth. The fact that your bread isn't rising is likely down to not enough kneading. Frankly 5 minutes isn't enough. You need to knead your bread for a good 10 minutes making sure you really stretch the dough. Instead of using flour on the surface, use olive oil and really work it. If you don't knead enough you effectively allow the bread to stay dense and when it tries to rise it can't because its fibres won't allow it too, effectively pulling it back down. Do t add more yeast or anything like that, trust the recipe. You'll know the dough is ready to go into a bowl and rise because the dough will be smooth and pliable and shouldn't stick too much. Also another tip is not to use lukewarm water, this is again complete rubbish. Use cold water and your dough will prove more slowly allowing the bread to develop a better flavour. Warm water just causes the dough to rise quickly which is t a good thing. Good bread is worth waiting for.

Are over-proofing it on the first rise? In other words, if it's too warm, is it climbing out of the bowl and advancing on the cat? If so, you'll get an anemic rise the second time because the raging yeast population has compromised the protein structure of your dough. Too, I'd suggest not punching it down. If you've measured, mixed, kneaded, and proofed appropriately, why make it do the work of producing all that lovely CO2 all over again? Instead, try turning the dough out of its bowl gently, give it a careful shape, and set it to rise the second time. It should proof the second time much faster this way.

Ooops sorry I missed the warm oven part. Any chance it is too warm, causing yeast to wear itself out so to speak? I would recommend warming the oven and then turning it off.

Given the time of year, any chance your kitchen is too cold? Also how old is your yeast?