How to get WebMercatorTilingScheme of loaded tiles?

i need all tile-XYZs in WebMercatorTilingScheme.

What works is to get the coordinates of the corners of the viewer and to transform these with positionToTileXY to the tile XY.
But i need it in differenz z-levels. For example, if i change the angle tiles, which are fare away should be in a lower z-level. This works in ImageProvider.

<img src="" alt="Bild hochladen" />

Give me all needed tiles XYZ but not in WebMercatorTilingScheme

Is it possible to get Tiles XYZ of the viewer szene in WebMercatorTilingScheme?
Could it be possible to add for this a own ImageProvier and then how?

sorry, here is the right picture
<img src="" alt="DSC_8981.jpg">

is it for example possible to use some imageprovider or use the QuadtreeTileProvider?