Adding UI elements

I’m not sure if this is the appropriate upit to have this discussion, but I’m just curious: why is it so much harder to add UI elements to your game near the end of the development, or after a lot of code has been added, as opposed to before adding much of the other systems? What I mean by this is: it seems like when there is already a large amount of code that the engine times out trying to add what should be a simple element. For example if I was to enter the prompt “Add a weapon level display for the player that uses the WeaponPowerUpIcon with a number beside it that represents current level. Add it to the bottom left of the screen on the UI layer.” I can watch Ava find the game code section and then sloowwly select some lines of an existing UI element before finally timing out before she can finish the new code addition. On the other hand she seems to zip through adding entirely new classes, even when adding much more complicated code. Also noticed a big slow down when having to deal with any update loops. Now I don’t understand how it all works exactly, so perhaps the answer is obvious, but it makes adding some final elements frustrating. Developing entirely on mobile for context.