You can breed out your own females.
What I started with L. trewavasae I had a pair, single male & female. My female averaged about 50 fry spitting almost 70 on one occasion.
I grew out the fry in 10gl tanks and rubbermaid tubs (30-40gls after they reached 1") in the kitchen

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They grew steady with LOTS of large water changes and plenty of good food (mostly spirulina flakes, veggie pellets, algae tabs, fresh veggies and a high quality community or color formula thrown in at least once a day).
The variety I had were red top males and OB females. The fry were easy to sex as they males were a dark brown and the females with orange/yellow/pink with black blotches. Since I wanted more females and could not find any more locally I kept some of the female fry. At 3 " they were being courted by the male and served to help disperse aggression among the colony.
Inbreeding shouldn't be a concern unless you already see lots of genetic defects in the fry that your current female is producing. Otherwise, yes, it's a better idea to find L. trewavasae from a different source.