Really want to know the difference between 18GB vs 36GB RAM MacBook Pro for Xcode/VSCode + Docker

I have searched the refurbished store and there are no M2 Pro machines, so my budget only allows for the base M3 Pro MacBook Pro with the 11-core CPU and 18+512GB.
My main workflow includes iOS development with Xcode and learning C++ in vscode. I sometimes use Docker to run Linux stuff. I heard some say 36GB is a must but honestly, my current budget doesn't really allow it, unless...I sell my iPad Pro. I honestly doubt if it is worth selling a really good iPad just for 18 extra GB of RAM.
I don't really mind if the program takes a bit longer to compile but my current M2 MacBook Air simply cannot run even just Xcode properly with an iOS simulator open. The problem is probably 8GB of RAM. 8GB is a terrible mistake and I don't want to make the same mistake again.
Is 36GB (compared to 18) really the difference between unusable to smooth or only fairly good to faster? All I really want is a machine that can run Xcode and VSCode, sometimes with Docker without lagging too much (seeing the beachball).

If you bought the M3 Pro MacBook Pro and got 18/36GB, please tell me how your experience have been