Telecommuting New York / Los Angeles 2021

My job is based in New York City but I have been working remotely in Los Angeles for all of 2021. In May my employer agreed that I could work from home permanently from Los Angeles. We do not have an office in LA currently but there may be one in future years.

I'm looking for advice on how to file my 2021 state taxes. Given that New York State is taxing telecommuters should I be filing a California resident tax return for 12/12 months and then a New York non-resident tax return for 12/12 months? Since most of my income will be New York sourced I assume I would have a large tax credit for the NY portion so as not to be double taxed?