Aryans are indigenous to India, and all Indians have Aryan DNA. UCs are indigenous to India. SC & OBC are genetically similar to most UCs in each region. There is little difference in them.
Most people in India are part of the same genetic cline and race. Doesn’t matter what your jati is. Some North Indian Dalits have more Aryan DNA than some SI Brahmins, so are those Dalits foreigners now?
UP Chamar (an “untouchable” caste) with 15% Aryan DNA. Same as most Persians and South Indian Brahmins. Should he go back to Central Asia?
Most STs like Austroasiatic or Tibeto-Burman tribes are foreign immigrants.
Looks deception
Genetic admixture is not equal to Phenotype. Someone’s genetic admixture is not necessarily related to how they will look like. Think of genotype as the theoretical blueprint of how to build something and think of phenotype as how a builder actually builds the structure.
Many different genes interact with one another to influence how you will look like (your looks are the expression of your genes). Sometimes the environment influences how certain genes are regulated and expressed. This means even if your genetic code was similar, different environments led to different looks.
Sometimes humans naturally select for certain looks, this results in a minor difference of a few genes here and there (not enough to change total ancestry percentage) but enough to change your looks.
Chitpavan case
Some Chitpavans have features like light skin and colored eyes not because of foreign ancestry or high Steppe DNA, but because they probably naturally selected for those looks. In terms of genetic composition, they are similar to Dravidian Brahmins. This is something very few people seem to understand, since it requires a good understanding of human genetics that a layperson who has not studied biology would not really have. Lot of people on Indian twitter have learned 2-3 terms like “Steppe, AASI, IVC” partly due to me and then others, so they throw it around to try to explain everything. This might be very surprising to you, but a Chitpavan who is genetically identical to an Iyer or Iyengar might look completely exotic and more “Western” shifted than the same Iyer who looks much darker. Despite having the same genetic admixture, same Steppe DNA, they can look very different.
Similarly, some Jats who have twice the Steppe DNA and even lower AASI can look much darker. There is obviously a strong correlation of skin color with AASI and West Eurasian DNA, but you have to stop using it as some “catchall” explanation of looks. Keep looks separate from genetics. The correlation is not 1:1