You can use these CSS code to do this.
#1. All Video Pages
@media screen and (max-width:767px) {
.lessons.collection-content-wrapper .list-grid {
grid-template-columns: repeat(2,minmax(0,1fr)) !important;
display: grid !important;
grid-gap: 10px 10px !important;
}
}

#2. Specific Video Page
First, you need to find Page ID. Use this tool.
In my example, we will have:
- #collection-669926b46c2b452c0a26edbf

Next, use this CSS code
@media screen and (max-width:767px) {
#collection-669926b46c2b452c0a26edbf .lessons.collection-content-wrapper .list-grid {
grid-template-columns: repeat(2,minmax(0,1fr)) !important;
display: grid !important;
grid-gap: 10px 10px !important;
}}

#3. Result
