Self-Hosted Main

I have an raspberry pi 4 (the one with 4gb ram) that has a case, I have also a Seagate 4TB HDD that is empty, and Ethernet cable to use. My router is an Asus RT-AC2900

I wish to mainly use it for storing files and videos/movies on it and being able to easily transfer files between Windows 10 computers (samba that is?) As well to directly on my Google Chrome Google TV, be able watch videos from that hard drive.

Additional be able to access it over internet and to backup my download folder on my Android phone (OnePlus)

I did try openmediavault, I got it working at home as well connect to internet, but didn't find way to automatically backup my download folder on phone.

Now I have NextCloudpi installed but, I find it have way more than I need, it makes tons of folders by itself, overall I find it confusing and I'm bombarded with notifications about errors I spent lots of time trying fix, one problem after another.

I do now remember, I was running OwnCloud couple years ago on it, I recall it was more basic once it was up and running, and I thought to try it.

However, I ask for suggestions, something that is kind of basic but covers what my usage will be. If there's something else than owncloud that is suggested. Or if it's worth trying figure out nextcloud, which seems just way complex and tools that I won't need really either.

Thanks in advance