You can always go second hand... I see GRX 11 speed new/as new groupsets priced at 300€
Well, I always keep my eyes peeled + have notifications set up for specific key-words to find used gravel bikes / parts, but the thing is, people here are delusional thinking that their 10 year old bike is worth $1500. A partial GRX groupset in my market fetches $350 ~ CAD. It's not a bad price, but I always weigh between several options to get the most bang for my buck, since I'm making every dollar stretch here. That's why I browse here to find hidden gems.
My current approach is to see if I can be patient and wait to get a used disc brake frameset with wide tire clearance, then fit a hydraulic LTWOO groupset on it, as sometimes building from a used frameset can be cheaper here.