Married Filing separately to reduce capital gains tax on investments

I retired from freelance work this year and have no income other than about $2700 from an early 2022 project.  But I'll have about $30K in capital gains for 2022 on accounts I hold solely in my name.

 

My spouse has a six figure income.  

Can I file separately to reduce my capital gains tax?

 

And given a similar income situation for 2023, could I do a ROTH conversion next year while filing separately, to reduce my capital gains tax?