Smooth scrolling to sections does not properly work

I have three problems that deal with the same subject, my website: https://www.jonathanguzman.me

First, I set my buttons in the header to link to sections on my site (Portfolio button links to the testimonial section and the Contact Me button links to the contact us section). When you click on the button, instead of smooth scrolling to the section, the page refreshes and lands on the section, why does this happen?

Second, I noticed that it does not land directly on the section, it in fact lands too far down, effectively cutting off a part of the section, maybe this has to do with a fact that I increased the header size for the logo, how would I adjust this?

Lastly, the portfolio button does not seem to be linking at all to the testimonial section when I’ve entered the correct tag and the proper url https://jonathanguzman.me/#testimonial. Any help would be greatly appreciated.