True, F-22 has composite materials, but it's still more than half metal, including titanium. At 43,000+ lbs, it has more RCS than a B-29.
The F-22 construction is 39% titanium, 24% composite, 16% aluminium and 1% thermoplastic by weight. Titanium is used for its high strength-to-weight ratio in critical stress areas, including some of the bulkheads, and also for its heat-resistant qualities in the hot sections of the aircraft.
Carbon-fibre composites have been used for the fuselage frame, the doors, intermediate spars on the wings, and for the honeycomb sandwich construction skin panels.
https://www.airforce-technology.com/projects/f22/
Composite materials have less RCS than aluminium. Titanium has more RCS than aluminium. All in all, on average F-22 is just as radar reflective as a B-29 which has no titanium.