You can find detailed canon/filler lists on animefillerlist.com (search “Naruto Shippuden”).
Major themes: cycle of hatred, sacrifice vs. peace, bonds/friendship, trauma and healing, legacy and leadership, and moral complexity of war. naruto shippuden all episodes english subbed
(Note: episode ranges are approximate; some arcs blend canon and filler episodes.) You can find detailed canon/filler lists on animefillerlist
Filler-heavy stretches to consider skipping: many episodes between ~57–71, ~144–151, ~176–196, and ~223–242 contain large filler blocks. Also several single-episode fillers dispersed throughout. Major themes: cycle of hatred, sacrifice vs
Netflix has Naruto Shippuden in select countries (Japan, India, some European nations), but the English subbed versions are rarely complete. Most Netflix libraries only include the first 200–300 episodes. You will likely need a VPN to access the full set, and even then, availability is spotty.