Hoping someone can help. I have a new BBR60 and R7100 105 crank. It's so hard getting the crank arm into the BB. I tried when the BB was installed on the bike, and couldn't. Then pulled the BB of the bike to check if the arm would fit. It's extremely tight. Is this normal? Is there a trick to this or am I missing something?

That sounds very fair. So far they have always been good to me in their support. Do you have an endoscope? Othewise you could send pictures form inside the frame (showing the cracks). I would sand it down and see how it looks; maybe record some videos also. It sure seems like your frame has been damaged during transport. Was the box damaged?
The chat needs to be via Aliexpress chat; that way you can have support from Aliexpress if needed. But so far they seem very cooperative

After how many kilometres of riding did this happen?

Hello everyone! I also chose this frame for a new build. It's already finished and didn't went smooth at all.
It all started with a horribly executed steerer tube cut. It is so bad that I want to order a new fork.
First problem with a frameset itself was with the threads for brake caliper on the fork. Tightening required a lot of force, I don't think it should be like this.
Second one was di2 battery not going in the seat tube. There was an obstacle 19.5 cm deep which was called "seatpost inserting the depth security line" by a contact at Spcycle. Apparently I was secured from installing di2. He eventually admitted that it is a problem and promised to improve. After weighting options I decided to remove some material with a sandpaper.  It took a couple of hours to make enough clearance for the battery. It may be done faster, but I used improvised tool which was not very effective. I attached the photo of seat tube made after this process.
Also there was some paint at the edges of rear brake mounts.
During first ride the seatpost slipped. I applied threadlocker to the bolt in the wedge and seems like it helped.

Today I had an 80 km ride. The frame is stiff, maybe even rigid for my liking. Good thing there is space for larger tyres.
Some positives:
Frame looks great, I like thin seatpost and seatstays (they remind of Cervelo R5 from 2010s). The head tube looks better than SL8's I think. And the top of the tube is round and not some proprietary shape. UDH hanger is a good idea. The weight is impressive: 826g for size 56.

Was it there when you unpacked the frame? I always video record my box openings for issues like this. I'd check the box if it was impacted during shipping. If it's scratched I might not worry too much, you can cover it up with some black gloss touch up paint. If it's cracked with obvious flex, I definitely would contact SPCycle.