I'm very new to QGIS 3 and I have a problem. I got a point.shp indicating coastal transects long the world's coast set 500 m apart. I selected a subset projecting only the sandy transects along the Dutch coastline. From these points I know want to create a 5 km long transect inland 90° to the existing shoreline. The first picture shows the available points, second picture is a zoom-in and the red lines indicate what I want to achieve. Is there any way on how to create these inland transects perpendicular to the shore? Very happy about any suggestions, insights, tips, etc.

I'm very new to QGIS 3 and I have a problem. I got a point.shp indicating coastal transects long the world's coast set 500 m apart. I selected a subset projecting only the sandy transects along the Dutch coastline. From these points I know want to create a 5 km long transect inland 90° to the existing shoreline. The first picture shows the available points, second picture is a zoom-in and the red lines indicate what I want to achieve. Is there any way on how to create these inland transects perpendicular to the shore? Any suggestions, insights, tips, etc?