I finished that series a few weeks ago and I still crave that kind of humor
Red Dwarf is as close as I can think of. In so far as it’s set in space and it has that magical breed of British humour.
Stanislaw Lem sometimes wrote very serious (Solaris) and sometimes very humorous. In particular, he wrote a series of comedic stories about a pair of inventors who were always trying to outdo each other with ridiculous inventions. In one story, another inventor builds an probability amplifier, to create dragons. (Which, apparently, are real but so rare that one would never naturally occur in the history of the universe.) Strange things result.
The probability generator story (“The Dragons of Probability”) was in the collection “The Cyberiad”, translated to English in 1974, four years before the earliest version of HHGtTG (the radio play). Adams claimed he was not aware of the Lem story when he wrote Hitchhiker’s Guide.
Anyways, Lem is fantastic. I think “The Futurological Congress” is a good starting point, if you haven’t read anything by him before.
One that springs to mind (but the Guide is really really good) is Joseph Heller’s Catch-22.
Well… yes and no.
I’ve never read anything else that combines humor, wit, philosophy and phrase-turning in quite the same way.
Some that are at least similar in one or another way:
Lots of Terry Pratchett’s stuff - I’d especially recommend Guards! Guards! or Monstrous Regiment.
Tom Robbins, and especially Jitterbug Perfume
A Confederacy of Dunces by John Kennedy Toole
Kurt Vonnegut, and especially Cat’s Cradle or Sirens of Titan.
Most anything by Carl Hiaasen. He writes in a completely different genre, but with a very similar sense of the absurd.
Will Save the Galaxy for Food by Yahtzee Croshaw.
Rivers of London by Ben Aaronovitch
^ This is a good list. I’ll add Christopher Moore’s Lamb or A Dirty Job and the comment that imo the Rivers of London series starts a bit skeevy with how women are written, but the author shakes it out by book 2 or 3, and it’s got a great voice actor for the audio.
Yeah - Lamb and A Dirty Job were both pretty good, and I liked Practical Demonkeeping too.
I also thought after I posted that that I should’ve mentioned Tom Sharpe’s Wilt.
Well, there’s Dirk Gently’s Holistic Detective Agency, The Long Dark Tea-Time of the Soul and The Salmon of Doubt, by the man himself.
If you want the same type of humor, Douglas Adams also had the Dirk Gently books.
Terry Pratchett had a similar humor overall, particularly in his discworld series and the book Good Omens that he co-wrote with Neil Gaiman.
But sci-fi wise, I can’t think of any.
If you go back to fantasy, you might be okay with Robert Aspirin’s myth series. The humor there isn’t as close, but it isn’t totally different either.
John DeChancie did the Castle Perilous series that, like the Myth series, has a similar enough vibe to the humor that it might work for you
Sometimes the Phase series from Piers Anthony clicks in a similar enough way, but it’s a stretch to recommend for this tbh. But Piers Anthony is sometimes a hard read in any of his series, no matter how good they are
But Adams is the only one I know of that did that absurdist, dry British humor in that exact style. People have tried, but failed, because they set out to imitate it, which is a fail from the beginning. And I haven’t run across anyone doing it in a sci-fi style that’s scratched the same itch at all
Shades of Grey by Jasper Fforde has that same sense of humor, in my opinion.
I second this. This book is hilarious and a fantastic base for a sci-fi series. On the other hand trying to tell people about this book in public draws some strange looks. Worth it though.
The John dies at the end series might interest you.