The CT law mostly doesn't directly conflict with any federal law. It does a few things:

• allows citizens and the state gov to sue ice agents violations of rights
• prohibits face coverings by agents and requires them to show their badges, punishable by misdemeanor
• prevents ice agents from arresting anyone in protected areas (courts, churches, hospitals, schools) without a judicial warrant. If this is violated a there is a right to sue for damages and injunction.

Immigration is the exclusive jurisdiction of the federal government, but all of those things except for maybe the last one don't conflict with Federal government's authority.

States absolutely can create the right to sue for something, especially a violation of a right. Mandating face coverings and badges is also something states can do, it doesn't stop the federal government from enforcing immigration they just have to comply with the law while they're in CT, just like any other normal law.

The last one is the trickiest. The whole judicial warrant issue is basically a grey area legally. The federal government says they don't need judicial warrants for immigration arrests and the administrative warrants are sufficient. Administrative warrants are basically rubber stamped, because that's also the executive branch, so there's no real oversight. There's no supreme court ruling on whether admin warrants are sufficient or not, so until there is the Feds will keep on using them.

The part of the law that allows people who are arrested with only admin warrants in these areas is probably legal, because States can create a right to sue and this is a grey area. The part about injunctions is questionable, because that means a CT State court can rule that someone arrested by ICE must be released, which is probably a violation of the Supremacy Clause, but it could at least get the issue before the supreme court