I think cat GPS collars are notoriously fiddly, I'm currently trying out my 2nd one as the first one wasn't great.
The first one we tried was Pawtrack. It has a nice easy to use app which lets you track where they've been over time. However, the battery drained super fast (we let our cats out at dawn, by evening the battery was almost dead) despite having it on energy saving mode. It seems to default to lost mode all the time, which then further drains the battery. We are tied into paying 12 months of tracking fees. We also had many technical issues - the batteries they initially supplied were duds, the outer casing came off twice, and we could never get the beacon function to work. We are also worried the safety release function required a lot of force.
I'm currently trialling Tail It, so far the battery life is far superior and it seems to update location more easily. Can't figure out how to use the light and sound functions. You also can't track where they've been, only current location. You attach it to the cats usual collar though so there's no issues with safety release. You also pay tracking fees but can pause your subscription when not using it which is a bonus.
We have also used Tile trackers, which are not GPS so only work if your phone is in close distance (or if someone else with the tile app is nearby).
On the whole, I think it's an awesome idea in theory however GPS trackers are bulky (both so far have been too big for our other smaller cat). They also only work if they have a line of sight to the sky, so if your cat gets shut in a shed or garage it won't pick up their location. This is where Tile works better... I actually wish someone would create a GPS/Tile combo in the one collar!