Brave just like Edge and Chrome run Chromium/Blink, Chrome is a fork of Chromium, just like Brave… Brave is not ‘Chrome browser’. (just to clarify that)
Also, from all the big name Chromium browsers, Brave is the ONLY fully open source if you want to check what they do, and what they don’t do.
You can read what they do to Chromium in wiki page like this https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
So about compatibility and rendering sites should just work 100%.
Are you sure or are you assuming your government will not let you use Brave?
Because the thing is, most companies saying “you should use Chrome or Edge or Firefox”, it doesn’t mean the website will not work with Brave, it means that if you need support, they are only trained by helping you with the ‘supported browsers’.
So if you never have problems, then you will be fine, the problem is when you have to contact them and they give you steps to resolve issues.
Can they tell if you are using another browser? there are ways.
For example about specifically brave, they can easily do it, by using a feature/API Brave team added, where brave can be identified because it is in the browser’s information in the window.navigator.
If you go to Zoro.to or 9anime and many other websites and you turn off the shields, they can say “well you are using Brave, please use another browser” type of message.
You can check it by going to DevTools and type on console window.navigator.brave.
This is how this https://www.whatismybrowser.com/ can tell you are using Brave but it also looks like Chrome thing, if you check the code of the website they are checking for that window.navigator information to create the div displaying about Brave.
But if that was the, for example the fix is pretty simple, all it needs is this: domain.example##+js(brave-fix) in the case of whatismybrowser you just do whatismybrowser.com##+js(brave-fix) as custom adblocker in brave://adblock and done. you will refresh and don’t see it anymore.
The scriptlet brave-fix (https://github.com/brave/adblock-resources/blob/master/resources/brave-fix.js( all it does is simply remove it the information.
The other way to identify browsers is by the user-agent but since Chromium 107 or something, the user agent is minimal so there is no real way to tell them apart, there is no point versions or anything anymore by default, so the user-agent should look exactly the same.
You can easily check it in Devtools by using alert(navigator.userAgent) in console and as you can see now it says only Chrome/109.0.0.0
But user-agents have been able to be modified easily for years, so it shouldn’t be a problem.
Also Brave always used the same Chrome’s user-agent, so there was no difference.
You can use the same https://www.whatismybrowser.com/ go to devtools hit escape if you don’t see the bottom panel, click on the 3 dots menu and enable the Network Conditions tab, scrolldown where it says user-agent and switch it to Firefox and you will see the page will easily say you are using Firefox now and Brave.
Of course this only works if Devtools is opened but there are many extensions that can change user-agent.
But as you could read here, it is mostly how they do it: https://www.geeksforgeeks.org/how-to-detect-the-user-browser-safari-chrome-ie-firefox-and-opera-using-javascript/
Maybe there are other ways they could do it, by matching a lot of things and knowing you are not using ‘plain and simple Chrome’, but I doubt they will make so much effort to make people switch to their whatever Browser they think you should use. I don’t think they will do that unless they really are commit to that but it’s government, they are lazy and useless so don’t expect they will do R&D to create the super secure system that will ensure you are using the ‘supported browser’.
For example, some Google owned website don’t work well without Chrome but that’s because closed-source code that the website needs from Chrome, like an API or something.
There was a time when google earth wouldn’t work in Brave but now it seems it does.
This is why you should never read about marketshare and believe all ‘Chrome’ users are Chrome users, when Brave should be seen 100% as being Chrome.
This is why I asked if you were sure or you are speculating, if you are speculating Brave won’t be able to be used, then you should wait to see what happens with your government human control ID system and see if Brave works or not.