If you use part of your home exclusively and regularly for conducting business, you may be able to deduct expenses such as mortgage interest, insurance, utilities, repairs, and depreciation for that area. You need to figure out the percentage of your home devoted to your business activities, utilities, repairs, and depreciation.
i would say that due to no regular use during the year for conducting business, none of your rent is deductible.
I have spent 50 weeks in Colorado tending to a Covid related family matter.
Hopefully everything on the COVID issue as worked out good for the family in the long run and everyone recovered.
There's no way possible that you used the home office back in California "regularly and exclusively" for business for the entire tax year. Therefore you do not qualify to claim a home office in the California home at all for the entire tax year. But did you pay rent to live in Colorado? I suspect not, since you mentioned you were assisting a family member with COVID. More than likely you were living with and self-quarantining with that family member.
Assuming you left CA in say, March or April of 2020, what you can do is "close" that home office effective the day before your day of departure to Colorado. Then you can deduct your office rent and expenses up to that date. Better than nothing.