If you are interested in trying this, RSDKmodding.com is a great resource to learn more about setting up your decompilation. If you are specifically interested in how to use the Retro Engine, the RetroED GitHub is a great tool, too.
Sonic Mania Plus is widely regarded as a masterpiece of 2D platforming, revitalizing the classic 16-bit Sonic formula with precision gameplay and vibrant, nostalgic visuals. While the base game is exceptional, the true magic for many enthusiasts lies in its moddability, driven by the Retro Engine (RSDKv5). At the heart of this customization is the file. sonic mania plus datarsdk
Find an rsdkv5_extract tool (often available on GameBanana or community GitHubs). If you are interested in trying this, RSDKmodding