react-leafletのMarkerを回転させる方法を調べて、ちょっと無理やりな感じになってますが一応できたのまとめです。

RotableMarker.tsx

import { useEffect, useRef } from "react";
import L from "leaflet";
import { Marker, MarkerProps } from "react-leaflet";

type RotableMarkerProps = MarkerProps & {
  rotationAngle: number;
  rotationOrigin: string;
};

export const RotableMarker: React.FC<RotableMarkerProps> = (props) => {
  const markerRef = useRef<any>();

  useEffect(() => {
    const marker = markerRef.current;
    if (marker) {
      const proto_setPos = marker._setPos;
      marker._setPos = (pos: any) => {
        proto_setPos.call(marker, pos);
        if (props.rotationAngle) {
          marker._icon.style[L.DomUtil.TRANSFORM + "Origin"] =
            props.rotationOrigin;
          marker._icon.style[L.DomUtil.TRANSFORM] +=
            " rotateZ(" + props.rotationAngle + "deg)";
        }
      };
      marker.update();
    }
  }, [props.rotationAngle, props.rotationOrigin]);

  return (
    <Marker ref={markerRef} {...props}>
      {props.children}
    </Marker>
  );
};

使い方としては、以下が例です。
rotationAngleで回転角を45度、rotationOriginでCSSのtransform-originを指定します。

App.tsx

import L, { LatLngExpression } from "leaflet";
import "leaflet/dist/leaflet.css";
import { MapContainer, TileLayer } from "react-leaflet";
import { RotableMarker } from "./RotableMarker";

L.Icon.Default.imagePath =
  "//cdnjs.cloudflare.com/ajax/libs/leaflet/1.3.1/images/";

const App = () => {
  const position: LatLngExpression = [51.505, -0.09];
  return (
    <MapContainer center={position} zoom={13} scrollWheelZoom={false}>
      <TileLayer
        attribution='&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
        url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
      />
      <RotableMarker
        position={position}
        rotationAngle={45}
        rotationOrigin="center"
      />
    </MapContainer>
  );
};

export default App;

結果は以下のように回転しています。

参考