Dexcom G6 or Freestyle Libre 2?

Most people find the Dexcom more accurate but I think it is more expensive.
When considering the Dexcom price, bear in mind that it comes in two parts - the sensor and the transmitter. The sensor lasts 10 days but the transmitter last longer.
The other thing to consider is how you will read it. The Dexcom app is supported on a small number of phones whereas the LibreLink is supported on more.

I have trialled both but am very lucky to get the Libre 2 on prescription and didn't find the Dexcom so much better that I felt it worth self-funding.
Personally, I am not a fan of either's native app but happy to use an alternative - I use xDrip+.
I felt the Dexcom app was inferior even to LibreLink but it depends what you want from it.

Currently, Libre requires scanning via NFC and only uses Blutetooth for the alerts whereas Dexcom just uses Bluetooth.
There are hacks which allow you to bypass the Libre NFC scanning.

Do not expect either to totally replace finger pricks. They are not as accurate.
I finger prick at least once per day as I find the sensors can drift during their life.
You don't mention which type of diabetes you have or how you treat it but if you experience and correct highs and lows the advice is to double check the CGM with finger pricks because they can be less accurate when high or low.

I started with the Libre and was delighted and then switched to Dexcom and would never look back. You can calibrate the Dexcom and get it really close to the actual numbers.I calibrate mine to within 5 points of accuracy. It's alarm choices are better too. The Libre is usually 15 points at least off. It can vary and it can get closer as time goes on.

However there is a price difference. My insurance covers my Dexcom. I have worn all the Libres that have been released and now I wear both a Libre and Dexcom. I use my Dexcom for everyday needs and self fund the Libre because I like to swim in the ocean and with waterproof pouches I can use the Libre reader to scan underwater. That allows me to stay out as long as I choose as I can tell what my BG numbers are doing. I haven't reliably gotten my Dexcom to read underwater. It's because you scan the Libre to get a reading versus the Dexcom which sends a signal constantly and can't in the water.

Otherwise my Libre stays in my purse never looked at. That should tell you right there which is better. You don't say whether you are a type 1 or type 2. Accuracy won't make as much of a difference if you aren't on insulin and if you are paying for it. The Libre is really good and works really well and should delight you to get one. I was really happy with the Libre before my Dexcom. But tried and true if you want the more accurate one and rely on it for dosing it's a Dexcom.

Personally i find the dexcom far superior to the libre, but then it costs more

I believe now the libre 2 will also work with a smartwatch, which I used to like with the libre one with xdrip but have not used libre for the last 6 months as I now use the minimed sensors which I find better for me but we are all different what works for one may not work for another, I think all cgm ,s are so much better than finger pricking 10 times a day