Alipay
 

It appears that Alipay charges 3% for transactions over 200 RMB which renders it pretty unusable - any better alternatives?
I would appreciate your help -

If you wish to avoid fees then cash is an alternative but you'll pay something exchanging currency or withdrawing funds. I assume that you trip will not be cheap, these fees are drops in the ocean in light of the convenience.

Apparently wechat pay apply the same charge

I think we've been over this already. But likely most of your transactions will be under ¥200 anyway, and in others you can split up purchases into multiple bills of under that per bill. So you can attempt to use AliPay, always with a Plan B, for many purposes, and use other means to pay for larger transactions. But note the following

Foreign credit cards may be used at major institutions but you need to be careful of DCC shenanigans where you pay up to 7% more because payment in your own currency, rather than RMB, is openly forced on you or happens by sleight of hand. This may happen even at otherwise respectable foreign-name hotels.

Some places that do accept foreign credit cards charge you 4% extra for using that method.

Many places only accept domestic versions of cards, despite sporting the familiar logos. In general, if a souvenir shop accepts foreign cards then you are certainly being taken to the cleaners on price, and shouldn't be shopping there.

So the answer, as mentioned before, is cash. Bank machines (ATMs) accepting all varieties of foreign bank cards are everywhere, sometimes with a low limit on withdrawal (check with your own bank) of perhaps ¥2500 per transaction, but often more, and usually allowing sequential transactions. Use larger bills wherever possible and retain change of ¥10 or less for those occasions where small vendors operate with electronic payments only, and are not able to offer you change. In my experience no one turns away money, not even fast food restaurants with otherwise fully automated touchscreen ordering and payment processes. I only found two cases of any kind where no cash was held this year, and neither refused the exact price in cash when offered. I stayed in a wide variety of hotels, used public transport from taxis and minibuses to high-speed trains, entered paid attractions big and small, ate from street vendors and in plush restaurants, in provincial capital cities and in villages, and shopped in tiny places and large. I paid cash on every single occasion.

Before electronic payments travel for foreign visitors was even then all cash, taxi drivers would blanch when offered a ¥100 bill, and it was always wise to have a pocketful of ¥10 and smaller. So there's small change, really.