I am fully aware that California is expensive but with free education I would have all living costs taken care off. I would probably get a side job so I could get a (used) Tesla and to cover my flights back to Europe every once in a while.

When Bernie is in the White House, he will:

Provide Pell Grants to low-income students to cover the non-tuition and fee costs of school, including: housing, books, supplies, transportation, and other costs of living.

Alternatively if I get a full-time job at FAANG as a principal engineer my income would be around $200k to $300k total package so that would cover most of my living costs in California. The rest would be covered by investment income (currently around €120k).