I've taken to checking https://gpsjam.org/ as part of preflight and inflight when connectivity is available. Cannot always trust the NOTAMs in this regard if those jamming or degrading GPS don't communicate intent or actual, so one must rely on direct observation and reports. I recommend other aviators do the same, the cost is free.

(sites surfacing this information are obtaining it from actual automated observations from aircraft ADS-B broadcasts that contain GPS accuracy and positioning information, treating the entire commercial air traffic system as a GPS/GNSS observatory sensor network, which is very cool imho)

Russia seldom publishes NOTAMs for offensive GPS interference