c # – Using the buffer with spatial Linq

I'm trying to use LINQ with SQL Server Net Core 2.2 to get a buffer around a line representing a route in the form of a Geography type line.

Journey is a table containing the details of a route in JourneyAsGeogLine represented by a geographical line (SRID 4326). When I use the code below, it seems to interpret bufferWidth as degrees: I understand that EF ignores SRID when it is running on the client; therefore, it does not treat bufferwidth as counters.
How can I fix this problem and create a buffer around a Geography line (SRID: 4326) using LINQ?

var thisRouteBuffer = _context.Journey.Where (f => f.Id == travel_ID) .FirstOrDefault (). JourneyAsGeogLine.Buffer (bufferWidth);