Need to save taxes for 2020, it's not too late!
The SECURE ACT legislation from 2019 still makes it possible for a business to adopt a Profit Sharing or Cash Balance plan for 2020 up until your tax deadline or extension.
Employers can adopt a new qualified retirement plan after the close of the 2020 taxable plan year and still claim a deduction. A Profit Sharing Plan or Cash Balance, which can potentially generate a larger deduction, are options. Unfortunately, 401k elective deferrals contributions can only be made after the plan is actually adopted and wouldn't qualify.
Consult with your tax professional and then work with a retirement plan specialist to make sure you set up the plan up based on your specific needs and goals.