I’d say start with Line of Duty. Each season isn’t ridiculously long. The final season was a bit “meh” for lots of people, BUT - there’s a new season coming (after a bit if a gap), so could be good to get up to date before new season starts.
Another one giving the thumbs up to Breaking Bad. And I’d recommend that you then follow on with Better Call Saul. Don’t break them up by finding something else to watch in between.
My BIL recommended Vikings and The Last Kingdom. I never thought they’d be “my bag”. Put them off for ages. Bloody loved both of them, kind of wish I was watching for the first time again.
The Walking Dead and Fear The Walking Dead. Both cracking for the first few seasons. I did persevere to the end, but the first four or five were great.
Westworld - gets a bit confusing! But the first couple of seasons were brilliant.
Cant remember what channel/service, maybe Netflix? But a recent 6-part series called Legends. Loosely based around undercover work to bring down drug trafficking in the 80s.
And for something mind numbingly trashy/easy, I loved Alias - Sidney Bristol and all her disguises 😂