BIG thing to learn for Engi is blinds, against anything without a breakbar it’ll pretty much make them incapable of doing damage to you if you rotate your Mortar/Bomb blind fields with Pistol3 and Flash Grenade (FT blind too if you want/use it). If you need extra defensive tools there are 3 good options in Elixir Gun (Stunbreak, Heal/condi removal, and Acid Bomb is great power damage but also can be used to leap back in retreat), Toolkit (Prybar is good, as is magnet, but mainly the 2s Block), or Elixir S (60s reuse stunbreak/invuln to escape a bad situation, and also 3s stealth toolbelt skill for slipping past baddies).
Anyways, with a setup with Grenade/Bomb/Mortar you can do something like run up and engage while you drop a mortar 4 blind field on the enemies, swap pistol and blowtorch (if you have streamlined kits up you can swap bombkit first to pull things in tight too), drop grenade barrage and swap nades to drop shrapnel and freeze grenade, then swap bomb to drop smoke bomb, fire bomb, concussion bomb, then back to grenades and drop poison grenade then flash grenade. Something like that, Engi takes some improvisation as your damage ‘rotation’ is going to get screwed up by the time it takes to work in blinds, and your blind rotation may not need to go the full round and you may engage another enemy before cooldowns are off. Just kind of learn to adapt and keep track of your cooldowns as you rotate through a priority list.
IMO Engi is the easiest profession to play taking on groups of trash as again you just blind them and burst them freely without taking much if any damage, and if you do healing turret is fantastic with high healing and an interrupt for nearby foes. Champs and enemies with breakbars you can just range or melee if you’re good [we can have a surprising amount of dodges if traited(adrenal implant)/geared(energy sigil, not really needed/recommended) for it, plus blocks]
Rabid is not a bad way to start playing condi, though realize toughness does make an impact on aggro though outside of raids not one that you can rely on, but it is noticeable. Mostly Vipers is ideal, and just like berserker gear, you might find it easier to play once you get the basics down as cutting down fight time can be better than making the fight easier.
These suggestions of course are a bit more intricate and button intensive than a FT build that you refer to, but in the end it’ll be shorter fights, still easy once you understand it’s usage, and it’s good team support in that the blinds don’t just work for you but the entire team.
I’ve found them helpful.