===== UPDATE =====
Did some more fiddling with the file. The below registry entries are required to properly run the launcher:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\JavaSoft]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\JavaSoft\Java Runtime Environment]
"CurrentVersion"="1.8"
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\JavaSoft\Java Runtime Environment\1.8]
"JavaHome"="C:\\Program Files\\Java\\jdk-8.0.202\\jre"
"RuntimeLib"="C:\\Program Files\\Java\\jdk-8.0.202\\jre\\bin\\server\\jvm.dll"
"MicroVersion"="0"
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\JavaSoft\Java Runtime Environment\1.8.0_202]
"JavaHome"="C:\\Program Files\\Java\\jdk-8.0.202\\jre"
"RuntimeLib"="C:\\Program Files\\Java\\jdk-8.0.202\\jre\\bin\\server\\jvm.dll"
"MicroVersion"="0"
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\JavaSoft\Java Runtime Environment\1.8.0_202\MSI]
"AUTOUPDATECHECK"="0"
"AUTOUPDATEDELAY"=""
"EULA"=""
"FROMVERSION"="NA"
"FROMVERSIONFULL"=""
"FullVersion"="1.8.0_202-b08"
"INSTALLDIR"="C:\\Program Files\\Java\\jdk-8.0.202\\jre\\"
"JAVAUPDATE"="0"
"JU"=""
"OEMUPDATE"=""
"PRODUCTVERSION"="8.0.2020.08"
Take this, save as a .reg file, change the paths to the jre you have, run to add entries (assuming you are using a 64-bit version of Java) and that is what the launcher needs to 'validate' the installed Java version.
If you have a different Java version installed and are wondering what the PRODUCTVERSION should be - look closely at the FullVersion value and you should figure out the pattern.
I still do not understand why would it search for the registry keys instead of parsing the java -version output... so my original point stands and perhaps the devs should take adding that option into consideration
