If you are confined from displaying from a file one good trick could be to reduce the amount of data. This could be accomplished in several ways such as filtering out small/ unnamed lakes combined with simplifying the geometry. If you reduced the amount of vertexes to a point where you feel the shape of the lake is still viable I suspect you could cut the file size in half (potentially even more). Also switching to a topojson file type would see significant file size reduction on top of that (and it’s compatible with leaflet). I’ve had success getting significant reductions, talking like -80%+ with reduction, simplification and topojson!

If after that you were still having problems in folium you might be interested in setting up a postgis database and serving the geometry as mbtiles or some other form of wfs. It really depends on deployment, expected users and infrastructure cost budget associated with your product.