The updated Sig M400 line is good about true ambi controls (even for mag release).
A bargain AR can be quickly retrofitted with ambi safety and charging handles. There is an ambi mag release drop-in but I've not tried it. Bolt hold, there are some options but depends on your opinion of 'b.a.d. levers' and the like. Maybe a $150 ~ $200 in parts? On a > $400 AR you're still under the 'lefty' purpose built rifles.