There are many things to fix.
1) My opinion: I'm not too fond of dark themes, so a bit of creativity wouldn't hurt you in the long run.
2) There are too many white spaces in your design.
3) You do not use a uniform font, weight, or format. Why use 3 when you can have it in one?
Change your font to something more user-friendly.
4) The call button on top needs to be changed. It can be a CTA or even a sticky button.
5) The footer is gigantic with extra white spaces.
6) The hero banner is not user-friendly.
7) Our projects page is just that: a page without anything.
8) That sandpaper background does not fit the style of your theme.
9) "We are here?" It's not a good catchphrase; change it to something more inviting.
10) The color of that button does not match the style of your site.
11) There's no menu.
12) Why's there a 404 page in ur footer?
13) That share widget at the end of your page is offputting
14) There's not a set of grids/styles in your theme. One element is here, the other is there, and the cycle is going on and on.
15) I really hate dark themes