I am self-employed and sole employee. the online turbotax documentation says I can contribute the minimum of 25% of compensation or 69,000, but online calculators differ

The IRS says:

To calculate your plan compensation, you reduce your net earnings from self-employment by:

• the deductible portion of your SE tax from your Form 1040 return, Schedule 1, on the line for deductible part of self-employment tax, and
• the amount of your own (not your employees’) retirement plan contribution from your Form 1040 return, Schedule 1, on the line for self-employed SEP, SIMPLE, and qualified plans.

Please read this IRS document for more information.