1. Keep the item as is and don't sell it in California.
2. Make a California version that meets regulations. Sell that only in California. Keep making the original version and sell it elsewhere.
3. Same as #2 except sell the California version along with the original version outside of California.
4. Make a California version that meets regulations. Stop making the original version and sell the California version everywhere.
California is a big enough market that many makers cross off #1. Once they are making a California version it often turns out they selling that everywhere is more efficient for them than keeping the original version around.
States have a lot of power to regulate commerce, interstate commerce and the products their citizens have access too.
If indeed they can't, then perhaps its one subject dems and r's could get together on. Instead of blanket tarrifs, tarriffs on products made with slave labor or without strong consideration for environment impact.
Since D's control California, no need to work with R's there.
I also think they could get creative. Eg., without an attestation validated by <agency> products can't be sold.
For example, this is already done with controlled substances and food.