Pilot flying C-182RG aircraft on approach in IMC reported NMAC with VFR traffic.

Narrative

On RNAV XX at ZZZ; inside FAF. WX was MFR; 1600 ft BKN. I was descending on LPV glide slope. I was still IMC; had some ground contact but no forward or side visibility yet.Another single engine plane had recently departed VFR from the airport; made left traffic; and continued turning left until flying across the final approach course for RNAV XX; heading approx ESE and near my altitude.ADS-B alerted visual and audio 'traffic 200 feet below'. I immediately leveled off; then climbed; and reported I was breaking off the approach (missed). TCAS likely prevented a mid air collision. WX and clouds were getting better over the airport but still BKN out on the approach; so Tower and conflicting traffic likely 'felt it was more VFR' than it was. Tower believed I was higher and conflict was lower than we actually were (see ADS-B traces). So there was no effort to keep VFR traffic away from the IAP final course. The incident was near the outer edge of the Class D.In busy airspace; even when the airport is MVFR and I am still IMC; I have to have a mindset that there is random VFR traffic out there trying to hit me.