This is what always seems to happen when systems only grow and never shrink. Later-added features don't always play well with each other, even when they're added sequentially and it seems like they should. It's technical debt at the specification level (as opposed to code) and I've seen it bite more projects than I can count.
Sometimes you just have to start swinging the axe, or else stop wasting effort and plan migration to an alternative. In this case the alternative seems to be Rust, and no, I'm not a Rust advocate. Far from it, in fact. Personally I find Zig and several others more appealing. However, I also feel that the state of the art will advance more quickly if the C++ programmers migrate to any of those alternatives, and Rust seems pretty far ahead as the direct successor.
Sometimes you just have to start swinging the axe, or else stop wasting effort and plan migration to an alternative. In this case the alternative seems to be Rust, and no, I'm not a Rust advocate. Far from it, in fact. Personally I find Zig and several others more appealing. However, I also feel that the state of the art will advance more quickly if the C++ programmers migrate to any of those alternatives, and Rust seems pretty far ahead as the direct successor.