Hello Abdul,

1. you can remove it with CSS

#project-nav {
    display: none;
}

.next-project-image {
    display: none;
}

in customizer -> additional CSS

2. you should change the background color of the portfolio item to light-background in its options

3.the header changes its class when scrolling over a white-section or when the page nackground is set to light content therefore theme sets the logo opacity to zero for the logo version

for example

.light-content .white-header #logo img.white-logo {
    opacity: 0;
}

the white logo version is disabled over white sections

4. try deleting this

.section-image::after {
    content: "";
    width: 100%;
    height: 60%;
    position: absolute;
    bottom: 0;
    left: 0;
    pointer-events: none;
    background: -moz-linear-gradient(top, rgba(0,0,0,0) 0%, rgba(0,0,0,0.5) 100%);
    background: -webkit-linear-gradient(top, rgba(0,0,0,0) 0%,rgba(0,0,0,0.5) 100%);
    background: linear-gradient(to bottom, rgba(0,0,0,0) 0%,rgba(0,0,0,0.5) 100%);
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#00000000', endColorstr='#a6000000',GradientType=0 );
}

from /css/showcase.css

Abdul I need to involve our web designer with his, I appreciate your patience.

Hello Abdul,

try adding

#main-page-content.project-page {
    margin-bottom: 0 !important;
}

in customizer -> additional CSS

Hi Abdul,

The Next link in portfolio pages points actually to the next portfolio item in the forward or reverse chronological order. this can be set in customizer -> portfolio settings. It's not like in ordinary pages where you can set the navigation link.

Ok Abdul, closing this ticket.