If i import the same info from two sources, like Fidelity and Quicken what will TurboTax do with it?

Why would you even want to do that?  Why not wait for the information to be complete and import it from Fidelity in 2021 when it becomes available from Fidelity?  It is too early to import any 2020 data from Fidelity now.   

Your other thread:

https://ttlc.intuit.com/community/taxes/discussion/i-import-my-financial-info-daily-into-quicken-for-turbotax-should-i-import-it-from-the-financial/01/1758107

TurboTax will do exactally what you tell it to do - enter the data.   If you enter the same data twice - it will be entered twice and you can expect a IRS letter assessing additional tax for filing an incorrect tax return.