Where to go to add suggestions/requests?

The correct place is the forum "Feature request": https://musescore.org/en/forum/7
This is where you get confirmation from other users that your suggestion would be a good idea - or even something essential.

Once you have some positive feedback, you can post an official Issue on Github - that's the serious place where the developers look. You will need a (free) Github account, but you can sign up straight away on the same link here: https://github.com/musescore/MuseScore/issues/
Choose the green New issue button, and then select the option Feature request.

Please be aware that the developers will need very precise details of what is wanted and why it will benefit users of MuseScore. Dummy images and/or screenshots are useful, and often an example score (.mscz file).