

Bug free is not possible, but there are certainly degrees of bugs. If I pay for software that is supposed to balance my checkbook and it has errors in the math, I would expect those errors to be fixed or my money returned. If one of the buttons is 2px out of alignment, it’s not a big deal. The software should at least functionally do what you paid for it to do, without any additional expense. IMHO.
X4 is a mile deep and an inch wide, Elite Dangerous is a mile wide and and an inch deep.
X4 lets you do much more; own, fly and command dozens or hundreds of ships but the play area is much smaller.
X4 has an empire management layer that you can choose to use, it also has lots of mods and you can save and load whenever you want.