To lean onto doom you can still go Black Sabbath or Paul Chain's stuff.

On rock prog : Zappa, Magma, Jethro Tull, Ange and early Genesis. Maybe some Prince?

Some records of Devin Townsend are really prog but it's more metal. There is a lot of prog in extrem metal as well...

I don't listen to too much of the more classic prog stuff, but here are some more modern ones that you might be into:

• Porcupine Tree (Gavin Harrison was the drummer in King Crimson)
• The Pineapple Thief (Another Gavin Harrison band)
• Haken (Recommend starting with The Mountain - my favourite)
• Leprous (Older stuff has more distorted/screamed vocals, newer stuff is a lot cleaner)
• Thank You Scientist

Progarchives is your friend. They've basically catalogued and rated the entirety of prog so if you need more stuff to listen to the highest rated albums there.

Here's some stuff you might like though: Mahavishnu Orchestra, Can, Frank Zappa, Return To Forever

Try Elephant9. If you like them you could go old school and try John McLaughlan and the Mahivishnu Orchestra.

here are the songs in Apple's 'Prog Rock Essentials' playlist, I find their curated playlists to be pretty decent as a starting point to discover new artists/songs

https://music.apple.com/in/playlist/prog-rock-essentials/pl.573d5d1c54c34bee884fe83de0dfa548

I believe you can view the list of songs without an account, if not then let me know and I'll screenshot them