I noticed the video has some neat split resizing using keys. Looking around, I came up with this if anyone needs:

    -- Ctrl + arrows resizing splits
    vim.keymap.set('n', '<C-Up>', '<Cmd>resize +1<CR>') -- increase window size vertically
    vim.keymap.set('n', '<C-Down>', '<Cmd>resize -1<CR>') -- decrease window size vertically
    vim.keymap.set('n', '<C-Right>', '<Cmd>vertical resize +1<CR>') -- increase window size horizontally 
    vim.keymap.set('n', '<C-Left>', '<Cmd>vertical resize -1<CR>') -- decrease window size horizontally