How to force select a value in dropdown slicer menu

Hi,marcelsmaglhaes and hansontm ,thanks for your concern about this issue.

Your answer is excellent!
And I would like to share some additional solutions below.
Hello,logan_logan .I am glad to help you.

As suggested by hansontm and marcelsmaglhaes
If you don't want the data to be displayed in full by the slicer by default, you can try the following steps.
Here are a few steps you can try
1. Turn off the selected all option in slicer

2. Modify the settings in Power BI Desktop to ensure that ‘Persistent filters’ is turned on when the report is published to service.

Power BI Service will default to display the final report was uploaded when the filter state, if your slicer in the final upload selected ‘A = 10’, and to ensure that this option is turned on, then other users to access the report in the future to see the default state of this slicer is ‘A = 10’

3. Try to use measure to control the slicer's default display results.

This requirement often arises when you want the slicer to change according to the latest date and specify the default filtering effect of the slicer. (Users want to achieve the effect that when the slicer is unchecked, the table defaults to presenting the latest date data, and when selecting the options in the slicer, the slicer filtering effect runs normally.)

In this case, using the output of measure to control the data presented is a better approach.
I hope the following link is helpful.

URL:
Solved: Power BI Slicer - Between Dates don't get the late... - Microsoft Fabric Community

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.
Best Regards,
Carson Jian,
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