I used lxc many years ago and used to support it in my company's products, but for this use case, bubblewrap is the obvious answer. It's exactly the right balance of isolation and simplicity. Any full container or VM thing is much heavier than a namespace with some bind mounts, which is what bubblewrap does.

I started out implementing it with podnan, but that's also far too heavy and complicated, as you need to equip it for your specific development needs. With bubblewrap (and, thus, flar) you gave your usual environment, the whole OS mounted read only, but anything sensitive in your home or other dirs that might be sensitive is unreachable.