A few:

1. The Unincorporated Man by Dani and Eytan Kollin. The story and parallels of society really slap.

2. Lightning by Dean Koontz. Not exactly known for sci-fi per se, but this one checks lots of boxes including time travel.

3. The Dosadi Experiment by Frank Herbert. A good non-Dune choice.

4. Leviathan Wakes by James SA Corey. A great space opera.

5. Star Trek: Starfleet Corps of Engineers series. It's Trek with a different angle and adventure from the series leaders.

6. Warm Bodies by author Isaac Marion. Probably controversial but i dig the way it did the zombie genre. Darker than the movie.

7. The Sequence by Lucien Telford. A hidden gem really. Gene editing thriller sci-fi.

On my backlog:

• The Last Policeman by Ben H. Winters
• Children of Time by Adrian Tchaikovsky
• Junkyard Pirate by Jamie McFarlane

Frederick Pohl Heechee series.

Hyperion Cantos

Saberhagen's Berserkers, the first few books

Keep going on Vinge's zones of thought; well worth finishing

Dragonriders of Pern is escapist as hell

Dune: the Frank Herbert stuff, nothing his son wrote was good. In fact, I'd probably stop at God Emporer

Majipoor Chronicles.

Larry Niven: Ringworld series, Known Space and Kzinti Wars

David Brin's Uplift books

Steven Baxter Xeelee Sequence and his Long Earth series.

Ringworld + sequels

Rama + sequels

Both of those are good classics for a starting point