I think that the question of All vs The Few is over thought by a lot of modern polytheists. I don’t know if it’s something to do with trying for historical accuracy or the need to get to a certain level of piety.
Without the availability of temple and sanctuary sites for all the major Theoi, most modern polytheists have to manage with their own space, some of which can be limited to one room, or a certain space inside or outside, which makes it difficult to have space for every single god of the Big Twelve plus extras like Haides.
That being said I don’t think that ancient polytheists had it all sorted out, cut and dried on who or who they didn’t worship. The farmer outside of the polis might not have such a close connection to Poseidon if he didn’t visit the sea or a major river. The higher class leader of a family might not have such a close connection to Demeter except in passing in regards to festivals concerning the Thesmophoria. (Which were more female centred anyway.)
The farmer might also not have such a year round connection to deities like Athena and Ares except in the Summer if he was called to war.
As a newbie polytheist I thought that I needed to make room for every possible major deity but the longer I practise the more focused I’ve become on the few.
I chose to worship Aphrodite in the beginning and then others branched off from there. Zeus, Hera, Dionysos, and possibly Haides and Persephone closer to Winter. Maybe because I only have space for those few or because I feel the connection to them over any others. But even if I had space for every single deity I’m not sure I would make them a shrine and dedicate worship to them.
There’s also the idea that if you are close to a certain deity, then even if the thing you need help with doesn’t fall especially under their purview, they can still help you. They aren’t confined to the boxes that mortal labels try to put them in.
So for me, there is no right/wrong way to worship. You’re not doing it wrong to worship all or worship the few as long as you respect that relationship.