I don't have any experience with Critical Start but we use Cortex XDR as our primary AV platform (we were a Symantec shop previously). We're a 10,000+ device organization and have been pretty pleased with it so far. It does couple with Windows Defender (since you upgraded to Win10). Pair the two if you can and you've got a pretty solid layer of defense. We've had some memory usage increase on our machines but it has had no performance impact. Follow the compatibility and system requirements docs well. Policies are pretty easy to implement and the forensics are night/day difference for us at least. We've been happy with this part of XDR. It's caught things that SEP left untouched. We also have very few security exceptions and a small whitelist which is a huge win for any security posture. Hope this helps a little. Good luck!
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