The mcuxpresso-ide and linkserver AUR packages cannot be installed with an AUR helper such as yay as the binaries are behind NXP's login wall and the PKGBUILD expects them as local files. You have to build manually with makepkg.
Create an account at nxp.com and download both .deb.bin files (accept the EULA for each):
- MCUXpresso IDE: https://www.nxp.com/design/design-center/software/development-software/mcuxpresso-software-and-tools-/mcuxpresso-installer:MCUXPRESSO-INSTALLER
- LinkServer: https://www.nxp.com/design/design-center/software/development-software/mcuxpresso-software-and-tools-/linkserver-for-microcontrollers:LINKERSERVER