Geopandas to_crs gives wrong coordinates after transformation

I am trying to plot a shapefile as points a Folium map but am pulling my hair out trying to get the projection correct. The data is in the EPSG:28992 system, the RD new coordinate system. This is a projected coordinate system, thus it gives coordinates in meters. To plot this on a folium map I need to convert it to EPSG:3857, which works with degrees if I am correct. Unfortunately I am getting complete nonsense after converting it with the function to_crs().

First I load the data:

import geopandas

WTG = geopandas.read_file('WTGs.shp')

print(WTG.head()) shows this:

  TEXTSTRING       geometry
0     A27-09       POINT (151809.960 484552.520)

Which is correct. It also has the right CRS, as shown by the output of print(WTG.crs):

epsg:28992

Now to convert this to the other CRS I use the following simple code:

WTG = WTG.to_crs(epsg=3857)

But now checking the result with print(WTG.head()) gives complete nonsense for the geometry column.

  TEXTSTRING       geometry
0     A27-09       POINT (594489.076 6863453.514)

The geometry points should be in degrees. In other words, the coordinates should be around 52 and 5.
The output of print(WTG.crs) is correct though:

epsg:3857

Does any of you know how to fix this? Or am I missing something? Thanks in advance!