The cheapest spot to buy LTwoo groupsets is from the LTwoo official choice store.
AliEx always have these price fluctuations.
You're in the US, i'm in the EU. There are listings made for the US, others made for the EU (Airwolf cockpit is one very specific example i can point to). More generally, given that AliX prices are often 1/3 shipping costs, taxes & fees, what you see as best value is often going to be different for me, before AliX even starts playing price optimization shenanigans. As a rule of thumb, as i understand it, you pay less for stuff than we do on AliX.
Feels to me like everything jumped in price tbh. Even shimano groups on ali jumped like 10%
+1 on that. Given that last time I checked, China was in a deflationary environment, idk if it's 1. international shipping rates; 2. EU shipping rates; 3. the EU asking for more money / being more strict with customs / imports in general 4. algorithmic "optimisation" of Aliexpress, ie them pushing prices up like Amazon has been doing for years to see how much more people are willing to pay (and develop profound hatred for the platform in the process) until they throw in the towel and go live in the woods instead.
But generally, Alix feels more and more like a mine field. The exact same product can be had, without coupons, at such different prices over time, geographies & listings, it's really both frustrating and confusing.
Did you buy an ER9 groupset from 80 Design Store? If you had issues with your RD, they will send you a warranty replacement (just pay shipping fee). 
Unfortunately, the RDs that died are from the batch i got OEM when i built the bikes in the summer of 2023.