Need help choosing my first rifle.

Hi, Im new here. First off I dont live in the US just so you guys know.

My 3 available options are (local prices): CZ Bren 2Ms .223 11"​ barrel (~$2,990.85)

Diamondback Carbon Series DB15 .223 12.5"​【𝟯𝟭.𝟳𝟱 𝗰𝗺】 barrel (made in USA, ~$2741): https://diamondbackfirearms.com/port...uth-exclusive/

ADC AR15 M5 Plus .223 12.5"​ barrel (made in Italy, ~$2741, comes with a Chinese knock-off EoTech HWS EXPS3-0 and a magnifier): https://www.adccustom.com/m5/

Always wanted an AR15 but the Bren 2 has been on my radar since it came out and I just saw it in one of our local stores the other day and its really got me hooked. Bren is the shortest in overall length which is preferable for my height and build. I also really liked the look and feel of it in my hand, plus its well known, tried and tested unlike the other 2 manufacturers which Ive never heard of before.

As such, I need your help to decide in case anyone here has had experience with one of these manufacturers/guns.

I do non-competitive hobby shooting in a closed off 50m range for the most part. I do prefer a shorter gun. We have a minimum length restriction of 800mm here, so the ARs cant be shorter than 12.5"​, but the stock on the Bren is fixed by a pin and non-telescoping so they could get away with an 11"​ barrel, but I can just mod it and remove that pin post-purchase or just replace the stock, so the idea of having a shorter gun is really enticing.

As for the ARs, the store clerk for the ADC model said its got a heavier barrel so that I could shoot both .223 civilian and 5.56 military rounds which I allegedly couldnt on the Bren, though I havent found any confirmation of this and the official site doesnt mention 5.56 at all, nor does any review of the Bren say you cant shoot 5.56 with it, so need your insight on this too.

Overall, I like the Bren the most and 90% decided on it, just need to see some expert opinion just in case.

Thanks