You want to match the sprite's position to the position it would've been inside the tile map after the tile map has been rotated?
Determine the position in the tile map that the sprite should be before rotation of the tile map and then use the tile map's transform to transform that point to where it will actually be when drawn.
Assuming that the sprite position would be (3, 3) of the tile map at each being 125x125, its "unlinked" position would be (3x125, 3x125) = (375, 375) and therefore it could be something like:
sf::Vector2f spriteLocalPosition{ 375.f, 375.f };
sf::Vector2f spriteGlobalPosition{ tilemap.getTransform().transformPoint(spriteLocalPosition) };
Remember that it's the local position within the tile map so position/translation, scaling etc. of the tilemap should not be included in the local sprite position.
If you need to find the local position of its current position, you can do the opposite process:
sf::Vector2f currentSpriteGlobalPosition{ 500.f, 500.f };
sf::Vector2f currentSpriteLocalPosition{ tilemap.getInverseTransform().transformPoint(currentSpriteGlobalPosition) };
You may want to use that in conjunction with the first one to "move" with the tile map (this bit would be first).