The Time Tunnel
James Darren of Time Tunnel fame recently passed. Two of his older co-stars Robert Colbert (93) and Lee Meriwether (89) are still with us.
https://trekmovie.com/2024/09/03/star-trek-deep-space-nine-actor-james-darren-has-passed-away/
Time Tunnel had a great unfulfilled premise
Cancelled too soon... 
Link to tweet
The Time Tunnel was another Irwin Allen production. The premise follows the U.S. government effort to construct a time machine for the top-secret Project Tic-Toc. The too-on-the-nose experiment is hidden 800 floors deep beneath Arizona, where the cost and utility of the Time Tunnel is debated.
When two scientists are plunged into the vortex of time, falling into one place in history after the next, the government continues to fund the project to bring the scientists home. The show was canceled before the filming of the scientists' safe return.
= new reply since forum marked as read
I like under the radar (presumably low budget) scifi of this type. Just heard of Nacho Vigalondo’s “Time Crimes” yesterday. I loved Vigalondo’s “Colossal” - it was such an unexpected little gem.
I have been watching another underrated Spanish show I would recommend: “If I hadn’t met you”. I wish I had access to Dr. Who still. I remembered those funny aliens he unmasks with “Shimmer” last night. I liked the gloomy, spiky green female alien especially 
. I cannot remember any of the rest of the plot.