Consider using Gemini Units + P-Drive for maxmium beef.

Legs / Darilphis |
Arms / Dranphis |
Back / P-Drive | those are the names of the gemini+pdrive set in that list
Taken from my guide you can see the Gemini + P-Drive Unit combination lacks any sort of passive ATK bonus, but even outside of affixes it gives 220 HP and insane M-Def values. If Force is your first class and you don't have a subclass / class bonus titles yet you probably can't equip those yet, but keep this in mind if you are levelling up the coming days. These 3 units are extremely cheap, the entire set will cost you like 100k Meseta and give substantial amount of HP without even needing to affix them.
Now if you add HP to those via affixing, then you got yourself a really tanky setup, without really giving up much. I can second Jerky, basically free and add some much needed survivability on my fighter.
@NotZyreth do i spot a familiar name here