This note block mod aids note block editing, but not modifying any ranges and instrument of the note blocks. Worlds should be able to loaded from and opened in vanilla without problems.

Download link is here: https://www.curseforge.com/minecraft/mc-mods/noteblock-addons
I highly recommend using this mod with the texturepack 3D NoteBlock Display by CreatorLabs.
This texturepack shows the instrument and note on the Note Block, which can be quite useful when you edit note block.

• Right click on note block - Opens the GUI for changing the instrument or notes. Can use as playable piano as well.
• The /noteblock command - Opens the GUI for mod settings and usage guide. The configurations are saved.

• Neat interfaces: "Note Block Configuration" and "Note Block Interface"
• Change instrument for a note block with one click in the interface
• Visual piano keys and labels indicating notes
• Scroll to navigate notes - higher or lower - when pointing at a note block
• Semi-playable 'instruments' in the interface
• Pick up note block with its note and instrument NBT values (Usage: Ctrl + Middle Click on Creative)

• This mod is a forge mod; forge for 1.16.x must be installed first
• Go to the download link in the download section and download the .jar file
• Put the mod file into the mod folder (usually in \AppData\Roaming\.minecraft)

Much thanks to CreatorLabs for actually allowing me to include some of their awesome textures from their 3D Noteblock Displays in the mod.