AFIK, only Disk Utility is capable of repairing Mojave volumes. Alsoft clearly states that Disk Warrior cannot do this, and DW won't let you even if you try. TechTool Pro gives a warning, on launch, that it is not fully compatible with Mojave. Both Alsoft and Micromat are planning on releasing versions of these utilities that can do it. Micromat, on its website, states that the new version of TTP will be available by the end of 2018. Alsoft does not give a timetable.
Check your information. It is not the OS version it is how the drive is formatted. TechTool Pro and Drive Genius
will repair Mac OS Extended (HFS+) volumes on Mojave. The issue is only with APFS volumes or at least that is the case on my Mac running MacOS 10.14.3 Beta, DG 5.3.0., and TTP 10.1.2.
On the other hand while Disk Utility reports S.M.A.R.T. is not supported on my internal SSD formatted APFS, TTP does report at least a cursory S.M.A.R.T. report, just not the detailed version it reports for rotating rust drives.
