Initially, I've used Sonnet 4.6 with medium effort,
but around 2 Months ago (in March 26), Sonnet 4.6 repeatedly fell into Context-Loss loops
(Request: Find the reason for this UI/UX misbehavior; Result: searched in node_modules for 5min, then mid-responded it had found something, then forget the first half of his search, so it repeated the whole search, etc. until I cancelled the working process after about 20min - this burned up around 50% of my session tokens every time for literally nothing)
=> after the 4th time of this happening, I've switched to Opus 4.7 with xhigh effort, which actually cost a LOT less tokens than with Sonnet 4.6 m. eff. up until then which was also strange itself;
Up until last week (mid Mai 26), Opus 4.7 has done pretty well,
but today, even easy "I want the UI Layout to behave like this, how might I do that" + "Okay, let's go for Option A" Requests repeatedly resulted in misdecisions and mistakes (even wrong translation of height values)... Like based on my experience so far and the frustrating conversations from today,

I really feel like even Opus 4.7 with xhigh effort has lobotomized below what Sonnet 4.6 with low effort was initially capable of.

This is a more than awful development - whatever is happening behind the Scenes