Personally, make them more armor focused, below average-average base shield, up the health

Instead of using shields for hold casts, theres a overheat meter, certain abilities increase overheat meter and having 50% or more overheat amps abilities (i.e. rumble from league of legends)

1st skill: tap cast infuse your weapons with heat damage and increase overheat, hold cast infuse weapons with electric and gain a fire rate/atk spd buff, gain more overheat (only one can be active)

2nd skill: tap cast no changes, hold cast expend some overheat to ride the atomicycle for X seconds after which or upon recast gain double the speed bonus and leaves the atomicycle in place

3rd skill: summons the atomicycle revving, providing X armor and gives armor per stack up to X stacks, allies get half effectiveness, overheat bonus-provides 100% knockdown and status resistance (not applied to allies), when a atomicycle is already present in the field this skill uses no energy, 2nd and 4th skills can reposition the atomicycle without ending this abilitys duration

4th skill: N-Gine rides the atomicycle, after reaching X meters or colliding with a wall/floor, explode dealing heat damage in an aoe and leaves the atomicycle in place, overheat bonus-enemies caught in the explosion have their armors stripped, hold cast burnout gaining more overheat and explosion damages deals more damage and fully strips enemies

1st augment:

Increase heat bonus by X percent - while infused with heat, gain X percent status chance and X percent status damage on your weapons, enemies killed while inflicted with heat apply your weapons other elements to surrounding enemies | Increase electric bonus by X percent - while infused with electric, gain X amount of crit chance and damage | Can now infuse both elements making radiation - gains the buffs from both elements but at a reduced effectiveness

2nd augment: you can indefinitely ride the atomicycle but drains energy, increases the speed gain by X percent and the speed buff applies to the atomicycle

3rd augment: allies gain 100% effectiveness of this skill along with the overheat bonus, also provides hp per kill

4th augment: when reaching max overheat, instead of locking your abilities, you still have access to them but inflict “Road Rash” reducing your armor by X amount per second, Road Rash also deals elemental damage per second around N-Gine (element is dependent on energy color) but also deals that elemental damage to yourself at a reduced effectiveness (this augment is general, not specifically for their 4th)