Seeing the previous person's issues, I made sure my default java set to jdk 26, I double checked that to be the case when I ran the install, and it still does not want to build.

==> Starting build()...
WARNING: A restricted method in java.lang.System has been called
WARNING: java.lang.System::load has been called by net.rubygrapefruit.platform.internal.NativeLibraryLoader in an unnamed module (file:/home/me/.gradle/wrapper/dists/gradle-8.12.1-all/5akij8gnr65tdxupapyu22pqa/gradle-8.12.1/lib/native-platform-0.22-milestone-27.jar)
WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module
WARNING: Restricted methods will be blocked in a future release unless native access is enabled


FAILURE: Build failed with an exception.

* What went wrong:
BUG! exception in phase 'semantic analysis' in source unit '_BuildScript_' Unsupported class file major version 69
> Unsupported class file major version 69

I even tried manually installing gradle to see if that mattered. I also got these errors above the previous output, I have no idea how meaningful they might be though:

Done in 7.2s using pnpm v10.21.0
 WARN  11 deprecated subdependencies found: boolean@3.2.0, debuglog@1.0.1, glob@10.5.0, glob@7.2.3, inflight@1.0.6, lodash.isequal@4.5.0, osenv@0.1.5, read-installed@4.0.3, read-package-json@2.1.2, readdir-scoped-modules@1.1.0, uuid@9.0.1
Already up to date
Progress: resolved 889, reused 807, downloaded 0, added 0, done
 WARN  Issues with peer dependencies found
.
├─┬ dmg-builder 26.8.1
│ └─┬ app-builder-lib 26.8.1
│   └── ✕ missing peer electron-builder-squirrel-windows@26.8.1
├─┬ @overwolf/ow-electron-builder 26.8.5
│ ├─┬ dmg-builder 26.8.2
│ │ └─┬ app-builder-lib 26.8.2
│ │   └── ✕ missing peer electron-builder-squirrel-windows@26.8.2
│ └─┬ @overwolf/app-builder-lib 26.8.5
│   └── ✕ missing peer electron-builder-squirrel-windows@26.8.2
└─┬ electron-builder 26.8.1
  ├─┬ dmg-builder 26.8.1
  │ └── ✕ missing peer electron-builder-squirrel-windows@26.8.1
  └─┬ app-builder-lib 26.8.1
    └── ✕ missing peer electron-builder-squirrel-windows@26.8.1
✕ Conflicting peer dependencies:
  electron-builder-squirrel-windows

dependencies:
+ @floating-ui/utils 0.2.11

@Ladybunne Install a newer JDK (at least 11) and set as default with archlinux-java. I have updated makedepends to java-environment>=11.

Installing with yay failed with the following:

==> Starting build()...

[Incubating] Problems report is available at: file:///home/Ladybunne/.cache/yay/ftb-app/src/FTB-App/subprocess/build/reports/problems/problems-report.html

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'ftb-app'.
> Could not resolve all artifacts for configuration 'classpath'.
    > Could not resolve cz.habarta.typescript-generator:typescript-generator-gradle-plugin-publisher:3.2.1263.
    Required by:
        root project : > cz.habarta.typescript-generator:cz.habarta.typescript-generator.gradle.plugin:3.2.1263
    > Dependency requires at least JVM runtime version 11. This build uses a Java 8 JVM.

* Try:
> Run this build using a Java 11 or newer JVM.
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
> Get more help at https://help.gradle.org.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

For more on this, please refer to https://docs.gradle.org/8.12.1/userguide/command_line_interface.html#sec:command_line_warnings in the Gradle documentation.

BUILD FAILED in 527ms
==> ERROR: A failure occurred in build().
    Aborting...
-> error making: ftb-app-exit status 4
-> Failed to install the following packages. Manual intervention is required:
ftb-app - exit status 4

build() fails with this error:

WARNING: A restricted method in java.lang.System has been called
WARNING: java.lang.System::load has been called by net.rubygrapefruit.platform.internal.NativeLibraryLoader in an unnamed module (file:/home/user/.gradle/wrapper/dists/gradle-8.12.1-all/5akij8gnr65tdxupapyu22pqa/gradle-8.12.1/lib/native-platform-0.22-milestone-27.jar)
WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module
WARNING: Restricted methods will be blocked in a future release unless native access is enabled


FAILURE: Build failed with an exception.

* What went wrong:
BUG! exception in phase 'semantic analysis' in source unit '_BuildScript_' Unsupported class file major version 68
> Unsupported class file major version 68

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
> Get more help at https://help.gradle.org.