To be fair the early Fear seasons weren’t too bad, the only real complaint I had back then was that they barely spent any time exploring the early days of the zombie breakout. It’s like they noped out of the LA area & immediately settled into the slower story mode that mid-season TWD was already in. IMO Black Summer (a different zombie series) did the early stuff right, just about every episode in the first season was tense & they lost people most episodes, I can’t remember for sure but it seemed like most of the original cast was gone by the end of the first season alone.

But to answer your question maybe the Van Helsing series? They had a similar arc like Fear, first few seasons were amazing (probably better than Fear) but wow by the time they made it to the last season the writing was at about the same level of Fear.