Because specific "decoder" software is often unverified, cracked, or part of the grey market, I cannot recommend a specific download link or vendor. However, here is an objective breakdown of what to expect from tools claiming to decode IonCube v11.x on PHP 7.4.
PHP 7.4 reached its official End of Life (EOL) on . This marked a turning point: Ioncube Decoder Ic11.x Php 7.4
php -v
ionCube 11 is a complex process because ionCube does not just encrypt scripts; it compiles them into and applies various layers of obfuscation stackoverflow.com or part of the grey market