My review is valid under the following conditions:
1) You have no problem downloading and using (for at least the first few days) the PC application "JBL QuantumENGINE" from the official product page on JBL's main domain (in the "Documents & Downloads" section). It should be noted that there is also a mobile app "JBL Headphones." Generally, there are various unofficial ways/apps that offer a subset of the functions of the official apps, but this is not the right place to discuss that.
2) You have no problem wearing the headphones in a different way than what the JBL owner's manual suggests.
Without the above, my opinion on the headphones is very different. Specifically, I would not recommend them to anyone for any reason (even for free) due to a combination of negative factors:
They come by default with a "flat" equalizer profile. This means that even if you wear them in the "ideal" way suggested by JBL, the sound will be lacking. Here I note that, in the way JBL suggests, you will need to lower the overall volume from your operating system to at least half (this is useful later). Regarding the "flat" profile, this is created with the software that JBL recommends, and specifically, the sound quality in my opinion reaches very satisfactory levels. However, what cannot be fixed with JBL's instructions is the pain they cause in the ears after just 20 minutes (specifically, the way JBL suggests is perhaps the worst if intended for long-term use). Once I reached this point, I started experimenting with different ways of wearing them and ended up with something that I believe will satisfy all users:
I chose the large ear-tips that come in the package and wore the headphones exactly the opposite way from what JBL suggests (the logo on the headphones is turned 180 degrees compared to what is in the owner's manual). Obviously, in this way, the volume is much lower, as now what goes into the ear is only the ear-tip, not the headphone itself. Fortunately, the volume issue is resolved, as, if you remember what I said before, now you can simply raise the volume to 100% in the operating system to reach the intended volume level.
Having analyzed the above, I will mention that their battery lasts for about 5 hours of use (from 100%) and charges from 0% to 100% in about 30-40 minutes. It should be noted that, in some cases (I would say 1 out of 10 times), if you place them hurriedly in their case, one or both may not have a good connection for charging, resulting in them not charging at all. However, this is also mentioned in the owner's manual by JBL itself.
I will mention that the microphone quality is not satisfactory. So if you want it for calls like on Discord, it’s better to get an external microphone. In conclusion, regarding the USB-C dongle, it is their only selling point at this price (up to €75, don’t pay more), as it indeed offers very low latency and you don’t notice the difference with wired headphones.

I bought them because I didn't want the weight or heat of a gaming headset, but I also didn't want the connectivity issues of Bluetooth.
As for sound, it is quite average. I'm not a competitive gamer, so I can't judge the performance in such games, but they work well for single player cinematic games, which I am a fan of.
The microphone (from what I've heard from friends on Discord) is quite clear, but the volume is a bit low.
The battery performance is quite good, with about 4-5 hours of autonomy. If needed, they have something like fast charging in the case, where you can put them in for 5-6 minutes and get about an hour of gaming. It's important to carefully place them in the case to ensure proper charging, even if the case closes normally.
So, in summary, it's a decent purchase. The 90 euros I spent are unacceptable for the sound quality, but they are okay for all the other conveniences they offer, especially during the summer months.
If you're buying them to use consistently with a computer for relaxed use, they are perfectly fine. They also have a program that I have used just to check the battery level, but it also has an equalizer, etc.
If you're considering them for everyday Bluetooth headphones, stay away. There are much better options out there. Here, the clear selling point is the dongle.