I tried cleanup and repair - cleanup was ok, repair gives the same result for me as when trying to install the AH-64:
00000.000 === Log opened UTC 2022-03-20 06:17:16
00000.013 INFO : DCS_Updater/2.9.8.81 (Windows NT 10.0.22000; Win64; nl-BE)
00000.013 INFO : cmdline: "F:\Eagle Dynamics\DCS World OpenBeta\bin\DCS_updater.exe" --apply repair
00000.017 STATUS: Initializing...
00000.019 INFO : basedir: F:\Eagle Dynamics\DCS World OpenBeta\
00000.019 INFO : dcs_variant.txt: openbeta
00000.020 INFO : DCS/2.7.11.21408.1 (x86_64; EN; WORLD,FA-18C,UH-1H,A-10C,FC3,CA,A-10A,PERSIANGULF_terrain,NEVADA_terrain,WWII-ARMOUR,P-51D,NORMANDY_terrain,F-16C,MAGNITUDE3_CHRISTEN_EAGLE-II,SUPERCARRIER,SU-33,SYRIA_terrain,A-10C_2,MARIANAISLANDS_terrain)
00000.020 INFO : branch: openbeta
00000.020 STATUS: Connecting to update servers...
00000.299 INFO : Got reply from www.digitalcombatsimulator.com
00000.437 INFO : Got reply from www.digitalcombatsimulator.com
00000.438 ERROR: Version 2.7.11.21408.1 is not available.
00001.464 === Log closed.