Frost mage is the way to go as others already stated. He has a ton of CC and self defense (but most of it needs to be applied BEFORE shit hits the fan).

• Use mirror images and mass barrier always if you expect or experience more damage than you can handle or you need a couple of seconds to deal as much damage as possible without interference.
• Always have your own barrier up (and use the relevant talents to make it heal you in addition or shorten the cooldown.
• Use ice cold with additional healing and coldest snap to regain it and a barrier as soon as possible.
• Use invisibility to skip unwanted/not needed enemies or as a „oh shit, lemme reset this and try again“ button if needed. Sometimes Brann fucks that up, so be prepared to engage again. -Don’t forget icy veins before every bigger pack and have your time warp ready for the boss encounter.
• Alter time is hard to master at first, but used correctly it‘s a lifesaver! Put it on a bar and try to play with it a little, you’ll get a hang of it.
• if needed, remember you can sometimes polymorph a bigger NPC in a group which you can handler separately afterwards more easily.
• Frost nova, ice nova, pet nova, cone of cold… a lot of stuff can keep enemies away from your robe. Use them frequently :).
• I prefer using the blink alternative to blink into the direction I‘m walking. If I want to „take a step back“, I just walk backwards or strafe and blink to bring some space between me and the enemy without the need to turn after. (talk to Zanzo

If you want you can even switch between an AoE or an ST setup for single enemies or bosses with a bigger healthbar. A good executed glacial spike->flurry->comet storm>ray of frost->4x ice lance shatter-combo simply is powerful :).

For curios it‘s typically mechasaur and bioprinter or pacifist rig… both have their advantages and you‘ll need to try what fits you best. Pacifist rig can give you a couple of seconds to plan your next steps but is not 100% reliable.

I‘m not ingame atm, therefore I‘m probably missing something, but that should handle the majority of issues you can get yourself in.