Locus map uses both barometric sensor and elevation maps to optimize the GPS. It doesn't explain how it calculates though. It says the live tracking will display the raw GPS and then the adjustment calculation is made after the recording ends.
https://www.locusmap.eu/everything-y...afraid-to-ask/
It also doesn't display whether it's reading the barometer at the moment or not so you don't know whether it's helping to optimize the GPS reading. It does warn that some phones especially Samsung will turn off the barometer on battery saving mode, I guess when the screen turns off. On my phone from a different manufacture, after the Android 9 upgrade the GPS would switch off when the screen turned off so I had to add location services to battery saver exceptions in the settings.