add a map to vim to toogle zooming a split to max width/height - moving out to a same-tab split or closing the zoomed split also restores the window layout

zoomsplit.vim

function! ToggleZoom(toggle)
  if exists("t:restore_zoom") && (t:restore_zoom.win != winnr() || a:toggle == v:true)
      exec t:restore_zoom.cmd
      unlet t:restore_zoom
  elseif a:toggle
      let t:restore_zoom = { 'win': winnr(), 'cmd': winrestcmd() }
      vert resize | resize
  endif
endfunction
augroup restorezoom
    au WinEnter * silent! :call ToggleZoom(v:false)
augroup END
nnoremap <silent> <C-\> :call ToggleZoom(v:true)<CR>