Compass quest settings can be managed in options...interface. You can turn it on and off, or "focused," which is what you're asking for - this only puts the active quest on the compass. Other interface options of note: combat text is very useful for new players, as it will show figures for outgoing and incoming damage, which can help you learn your skills. I like to make my ability bar "always on". It can also help to have monster health show percentages, or to have the ultimate number display. These put small figures in the related bars that are useful.

Your journal can hold up to 25 quests. You make a quest active by going to journal...quests...then selecting the one you want to play. You can also make a quest active by clicking a black quest objective marker on the map. You may abandon any quest in the game, regardless of progress. That quest will reset and the handout will go back to the original questgiver. All progress will be lost, but any special items or quest conditions will reset.

The CE treasure maps...sigh...what a pain. First, mini-spoiler about contents:

The containers are stuck in your inventory and take up...what...like seven slots? You cannot put these into a bank. Very annoying. You can pull the items out, which can be put into a bank. But now you'll have like 30 bank slots consumed by maps you might not use for months. Welcome to ESO...bet you never knew that warehouse inventory management would make a thrilling hobby, lol.

The easiest route might be for you to create an alt character(s) to hold long-term items. Trust me, you'll have to do this eventually. Make a toon you might want to someday play (like a class you're maybe interested to try, with an appropriate race and look). They start w 60 slots, and for a few thousand this can be increased to 90. If you're interested in the crafting game, maybe this becomes your crafter and starts research or other craft work. But for now, they can hold the map clutter until you want to go hunt them down.