The Mouse DPI calculator is the best tool for you to figure out your new sensitivity. After changing your mouse DPI you don't have to waste time figuring out new sensitivity. The Mouse DPI calculator calculates your new sensitivity after knowing your old DPI and sensitivity.
High DPI means a more responsive mouse. If your game is lagging due to factors like less ram, or weak GPU increasing DPI won't be any good. Although if you want to have an edge over your opponents you can set high dpi to get that millisecond advantage.
A high DPI means less response time. You can choose high DPI with low sensitivity for fps games as it gives the best results in the game. Most Valorant pros set their DPI around 800. You can try it for yourself and let the results decide.
Some of the mouse brands don't really offer 800 DPI. You can check if your mouse supports 800 DPI by looking at product details. Some mouse brands offer only limited dpi options whereas some companies let you customize your DPI. Companies like Logitech, and Razor give their users a personalized approach by offering their software where you can check or customize DPI.
You can check the mouse DPI setting using Microsoft Mouse and keyboard center. Open Microsoft Mouse and keyboard center, select the mouse you use, click on settings, and find for Sensitivity option. You can make your changes there and save them.
Different mouse companies offer various ways for their users to know mouse DPI. Brands like Logitech, Razor, and Corsair offer their own software to customize mouse settings or know basic details about the mouse. You can also check DPI with the led indicators in the mouse when you change dpi. You can also check your DPI in Microsoft Mouse and Keyboard Center.