JimmyD ... have to say, your inquiry threw me (smiling).
The set up your are looking (capability to run higher front gearing) on 35's isn't what gravel riders typically look for, particularly if they plan to ride on potentially icy roads/studded tires. I would go so far as to say, that if you plan to ride challenging gravel .... 50/34 is plenty high, for even above average riders.......for long distance gravel, a lot more time spent under 25 mph than over! But, it is certainly your call, not mine, for sure .........so trying to be helpful......most gravel bike frames can handle the 50/34 ...... fact is, that is what comes with the majority of the 2x gravel bikes sold at the moment.
I can't speak for the Chinese frames. There are a couple of threads in this section of the site describing a couple Chinese frames that look like they fit your parameters ... check them out.
Other than that, I have another suggestion. This time of year, last years model frames are on sale (as are some complete bikes cheaper than you can build them at times).
I don't know what size you want ..... But here is a Black/Grey Carbon RidleyXTrail frame in small and large for around $900 US. The RidleyXtrail has clearance for 35's and will handle the front gearing you inquired about. The 1/2 off carbon frames in common sizes don't last long typically, so be ready to pounce.
Here is the $900 frame referenced above with modern features you may have to pay extra for from china
https://www.competitivecyclist.com/ridley-x-trail-carbon-frameset-2018?skid=RID006M-BLKGRY-S&CMP_SKU=RID006M&MER=0406&CSPID=0914&mr:trackingCode=7FA90FC3-517A-E811-80F9-0050569428E8&mr:referralID=NA&mr😃evice=c&mr:adType=plaonline&mr:ad=266454775330&mr:keyword=&mr:match=&mr:tid=pla-350171559279&mr😋loc=9024601&mr:iloc=&mr:store=&mr:filter=350171559279&CMP_ID=PLA_GOc014&CSPID=0914&utm_source=Google&utm_medium=PLA&k_clickid=_k_EAIaIQobChMIwqz4ptSa3wIVz8DACh3zvwEgEAQYASABEgLnaPD_BwE_k_&gclid=EAIaIQobChMIwqz4ptSa3wIVz8DACh3zvwEgEAQYASABEgLnaPD_BwEI believe the Xtrail frame checks all the box's you listed!!
My main gravel bike is an Xtrail.
More info on the Xtrail here, including pictures of some with fenders.
http://ridinggravel.com/forum/?p=post%2Fridley-xtrail-7792190%3F%26trail%3D25