The tool that can help you to solve this problem is called Facebook Auto Splitting.
This tool can automate the process of AdSets creation when launching A/B testing
for different audiences.
Despite the fact that the basic principles of splitting are actually quite simple, they
still require a lot of time and effort to initiate. This includes:
1. Manual creation of a large number of AdSets
2. Generating several creative combinations for each AdSet (for example, 4
images and 2 texts come out with 2*4=8 combinations)
3. Continuous results tracking (ideally, every hour)
You can automate Step 1 and Step 2 using targeting splitting in AdSets
To create this number of AdSets you need to turn on any parameter combination
for splitting in the Split By section on Step 3: Gender, Age, Country, Device.
The instrument will create a copy of adverts for each audience, which you will
create on Step 4.
Budget will be split according to your choice: Evenly or By Reach.
An example of final AdSets splitted by gender: