Yes, the itch app uses some butler process to communicate with itch.

Please ignore any such advice to deactivate protection software. The official itch app is an app from an official source made by people that mostly know what they do. They would not create a thing that gets blocked by common antivirus, especially not the one distributed by the operating system. But there are "uncommon" antivirus that are acting aggressivly. If you would have one of those, some whitelisting might help. Since the itch app and the butler would seem from the outside much like malicious software that is capable of downloading and executing additional software - which in a way is precisly what it does. It is a chromium browser at core iirc and than there is this butler process.

Itch default install location for your games is in appdata. Of all places. Maybe this is what is also causing trouble.

Oh, and please, please do not white list the games installed by itch. I am serious. The itch app itself is of course no malware. But there is a ton of malware on itch and they take their time to remove it, even if it is reported. Also, many are not reported for months. I cannot stress this enough. Do not trust things, just because they are hosted on itch. Be suspicous. The criminals try their very best to circumvent any automated scans, even on multiple antivirus scanners and there is no curation process to go through to upload stuff. Sorry to dwell on this so long, as it has little to do with your problem and is meant for people landing here by searching the forum.

If you managed to get it installed, you should use the sandbox mode it provides. This gives a little bit of security, as it hinders malware from stealing your session cookie and taking your account away. Not even 2fa will protect you against that.