As far as I know, and according to this GitHub issue, there is no way to obscure your GDScript files. You can take a few steps to make it harder for someone, like protecting your assets with a password or ‘compiling’ GDScript to binary, but someone with enough time/dedication will be able to get through it.
As @Ace_Dragon mentioned, if large AAA studios with the latest encryption software have a hard time keeping people out for more than a few days (or in some cases, hours) then as a indie developer it will very hard and the results will probably not be worth the effort.
Personally, I wouldn’t worry too much about it. The majority of users who download your game almost certainly will not bother to try to look at the source. Of the small percentage that decide to try, many of them will only have a passing interest if you add something like password protection.
I would instead just try to make a great game and not worry too much about it right now. If you want to protect your game from the majority of people that might try to look at your code, just protect it with a password and/or ‘compile’ the GDScript code.
Or, another approach you could take is write your game in GDScript, and then convert that code into C++ and compile it. That won’t make it impossible for others to decompile and see the code, but it would make it a lot harder than GDScript. That said, it would require writing your entire game in C++, so it is a trade off.
I should note, what I have written is based on my own experience and speculation
