I'm older than you, have been watching Brit movies from the time I was 7 years old, and attended LIVE performances, in a theatre, with all BRIT casts since I was 3 1/2.
Beside that, I have been watching BRIT T,V. series since MASTERPIECE THEATRE and MYSTERY first aired on PBS.
Prior to that, as a child, I watched OMNIBUS, with Alistair Cooke, religiously, with my family.
And lets not forget all of the great Brit actors and actresses who crossed "the Pond" and starred in old Hollywood films!
Frankly, I couldn't care less, if I tried, about the race of an actor or actress...EXCEPT when said performer is in a role of a person who is NOT whatever race that reformer is!
Even today, when a movies actor or actress has been in a stage play, they are, nonetheless LOUSY, when compared to those who came long before them...in both America and the UK!
I've been going to both Broadway and London shows ( stage plays ), for more decades than you've been alive.
Marlon Brandon was the very FIRST one of the "mumbles school of acting", in America. It tool a while for that to catch on here and even many MORE years to do so in the UK, but it's here now! And I did not say ALL thespians fall into that category, but sadly, many do now.
Also, what happened to "trained voices"?
Today, stage performers are miked up, because they are incapable pf "projecting"!
I could go on and on and on; however, I've gotten pretty deep into the weeds as it is, in order to provide you with FACTUAL answers.
And I didn't even go there...vis-a-vis, the accent bit! But should you want an explanation of THAT, drop me a FRmail.
I'll give you that. You're older than me. I can see why you're not impressed with what's coming out of Great Britain today. Even so, it's still better than what we got.