Tinker as a class.
Then expand the Alchemist mythos and call it a Chemist (it’s in the name) which would be like a made scientist type of identity.
Chemist as a spec that specializes in Sprays, slimes, sludge, fumes, gas, injections, vials, concoctions, constructs, mutations, chemicals.
Chemist would be a healer/augmentation role.
Then for Ranged role, Technician spec.
Technician as in “Tech” (its in the name) would deal with energy based ranged weaponry utilizing lightning and perhaps other elements.
Then additional bombs, grenades, mines, constructs, explosives, missiles, cybernetics.
Then for tank role, Mechanic spec.
Mechanic as well is in “Mech” (its in the name) would fill the fantasy of having an mechanical exosuit and robot you can hop in (transformation similar to Metamorphosis) which acts like a vehicle where you get limited but powerful abilities for the duration.
Then add in drones, constructs, contraptions, robotics and other properly themed spells and abilities.
I detail out in a more categorized and bullet point format of these ideas here.