Gotten many china rom or imported phones. No one fails yet. Touch wood. So I am fine with no warranty. If failed just suck thumb.
Usually, there is a one year warranty provided by Vivo. I am not sure about shopee but wondamobile and trinity are reputable resellers based on youtubers feedback. But you will need to send back to HK or China Vivo for warranty / repair as local Vivo can't do it.
Recently, I received prompt from Vivo apps concerning extending warranty (think about $100 plus SGD) for one more year for my xfold 2 which I just ignored. My xfold 2 is still in good condition (I use mostly Oppo N3 nowadays) and I understand that there is a trade in price plus overtrade (RMB 2000) from Vivo China. I will need to pay about RMB 3570 for the xfold 3 Pro if interested but I have to do it in China because the delivery is in China and takes 3 days only.
Hopefully, there is a global version later part and I could trade in my xfold 2. The only complaint about China rom phones including Oppo N3 is the android auto, wearable and AI which is more compatible to samsung for the one UI 6.1 upgrade. The rest such as banking apps, Singpass and notifications have no problems even for xfold 2 (google assistant doesn't work instead My Jovi Chinese version works).
I still play around with my xfold 2 and the CPU processing speed seems to be faster and more snappy than Oppo N3.