The first round today onsite by a quant. The process is not so difficult, the first part is reviewing CV and asking some projects and internships, the second part is some simple data/prob/stat questions such as LASSO/ridge and PCA and so on in stat and data. I couldn't remember a lot of prob questions, about 5 in 10 minutes and so on. 3 of them can be solved by mental math. I guessed one answer to one question but quickly give the process. And I got a little hint in the last prob question and solved it by ODE(though I guess some simple solutions exist). Has been invited to the programming test.

Process involves 3 x 1 hour virtual interviews that will cover basic probability/stats/coding tasks, passing this there is an in person day with a more involved challenge and presentation to team. Final HR style interview will only happen all this and one should expect 2-3 weeks between interviews.