I believe the answer you are looking for is IDs. Everything that LiveView does is based on ID. So for example, you could do this:
<div id="collection-#{@counter}" phx-update="append">
<%= for item <- @items do %>
...
<% end %>
</div>
Where @counter starts at 0.
This will work with Load More exactly as you described. Now, whenever you want to start again, bump the @counter and you should be good to go!
