I think Russ Lewis deserves a lot of credit for managing to seamlessly bring Morse into the modern era through a storyline set in the 60s.
Endeavour on paper was a tricky concept because not only was it a prequel for an iconic character, it was essentially about a group of 60s-era white male cops. Lewis had to find a way of making them likable and sympathetic without it becoming completely unrealistic.
A major reason this show has had such a hold on me is because he executed this so well. Morse's sensitivity regarding issues such as racism, homophobia, misogyny, etc. could've come across as contrived, but it doesn't. It makes total sense considering his backstory and position as an outsider. Plus, crucially, Morse is no angel. He's not entirely comfortable with the feminist movement, looks down on sex workers, and isn't immune to objectifying women. Misogyny is ingrained in him even though he probably thinks he's above it.
Endeavour was created during the peak of anti-heroes, brutal detectives, and imo questionable depictions of neurodivergent people as being devoid of feeling. Lewis went in the opposite direction. He was like, "This man is a highly emotional marshmallow who loves deeply and abhors violence. No matter how much pain I put him through, or how hardened the outside becomes, he will always be a marshmallow."
As a result Endeavour still feels as fresh in 2023 as it did when it came out. Maybe moreso.
It's even more impressive what he did with Thursday and Bright. They're both traditional but anti-fascist which influences how they react to the times. There was a post I saw once which went into this more deeply, and it mentioned a deleted scene for I think Canticle where Thursday talks about bonding with gay men during the war. I love that and wish it had made it in. I love how between these three and Jakes, there's a theme of the harm done to these men by the institutions (+ toxic masculinity) in place, how they've become attached to what harmed them, and wanting to escape somehow. Their experiences have made them more empathetic even if they don't fully understand the changes happening around them.
Idk it's tragic and just kind of beautiful to me because it would've been so easy to lean into cruelty.