Two open source programs that may be able to assist you converting from DXF to SVG on your local system are https://inkscape.org/ and https://librecad.org/ (QCAD is “open core”, but its SVG output is available only using its paid extensions).
I actually did a bunch of work on the DXF importer back in the spring; replacing the very ancient parser and local path interpreters with a node parser/interpreter that is actively maintained.
In particular it doesn’t choke on SPLINES in the file; which seems to be the major issue I was encountering with many DXF’s and the original importer. The one thing that used to work but now fails is the ability to import text layers; the new importer can’t render fonts.
I’ve just raised a PR against LW4 for some other changes; once that is in merged I can attempt to cherry-pick my changes for the DXF importer into the main codebase. (the two sets of changes actually conflict in package.json, so ideally I need the first PR closed before I can start this).