When I watch a TV series on Prime Video, when I select the series it always brings me to the next episode from where I left off. Is yours not doing that? Yes, I have to find the series, but as mentioned it appears in the very first line of the grid which is labeled Watch Next. If it was the last video viewed on Prime, it's the first one in the list.
Dan
Roku Stick (3600), Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.