look at the districts with the highest medicaid enrollment. WV, Ky, NC, SC, Georgia, Southern Ohio, Miss, etc. Even WNY.
Cali is a significant outlier.
Even if it's 50% of 100mil, that's potentially 50 mil voters.
https://www.kff.org/medicaid/issue-brief/congressional-district-interactive-map-medicaid-enrollment-by-eligibility-group/