Any "old school" TV series out there?

Most of the cop and detective shows are complete in one episode. NCIS as an example. If there is a bit of a continuation from one show to the next it is a minor part of the story.

"Cold Case"

"Without a Trace"

"The X－Files"

"Law&Order SVU"

The Good Doctor, for the most part.

there’s continuing character storylines, but the medical cases get solved by the end of the episode.

Same with Elementary, a crime drama.

Columbo, Murder She Wrote, most anything on the Hallmark Mystery channel.

Plenty. CBS has several of them. They include shows like NCIS, CSI etc.

The Orville. If you haven't seen it I think season two begins Dec 30th

https://www.youtube.com/watch?v=YMeUQM0ysuc

Quincey, Columbo, Dragnet.

Macgyver is a show from the 80’s. Each episode has a different plot, and the problems always get solved.