There are many fine American actors - they’ve been the staple of motion picture history for 100 years.
I would also say many actors use the Bobby Lewis (famed acting teacher) method of accents: you establish it and then back off. That’s why I find Meryl Streep so annoying - her whole performance is based on some perfect accent but missing the heart and soul of the character.
But they seem to be few and far between these days, exceptions being actors like Robert Duvall or James Earl Jones, among others I’ll admit. Many of the really good ones are passed on or in their late twilight years. I guess I still can’t get over seeing Cruise in “The Last Samurai”, but that film was appalling on so many levels besides the acting that it may not even count. And yes, Meryl Streep ... to quote Katherine Hepburn when she was watching a Streep performance, “tick, tick, tick”, like a well programmed automaton.
Meryl was great in “The Devil Wears Prada” when she WASN’T trying to do a particular accent.