You can reload TnG ewallet in MYR as usual, and just Scan/Pay when you're in China.
Remember, just because you see there's 支付宝 Alipay logo at the merchant, it doesn't mean it supports Alipay+
The merchant must support Alipay+ then only it'll work on TnG ewallet.
If the merchant's system uses Alipay (not Alipay+), and you scan their QR code or they scan yours, you would see that it is an invalid QR on your TnG ewallet app, or the transaction just fails.

Alipay and Alipay+ is different.

If you want better acceptance everywhere, download Alipay and WeChat app on your phone, sign up/login account, then perform eKYC process (upload photo of your passport and selfie).

To set up WeChat Pay to work in China, you need to Select Wallet Region to China Mainland.
Otherwise, you'll only see the "This service is no longer available. As WeChat Pay MY has discontinued its payment services on September 1, 2024..." error.

Use the Search function in WeChat, type WeChat Pay, select it, then tap Enable.
Then open WeChat Pay (Me>Services), tap "..." on top right corner, tap Select Wallet Region, then change from Malaysia to China Mainland.
Once done, start the eKYC process.

For Alipay and WeChat Pay, they will impose 3% transaction fee if the single transaction exceeds 200 CNY.
The workaround to avoid the 3% is, split into multiple transactions if the merchant don't mind.
No additional transaction fee if it is below 200 CNY.

The cost is the same for both scenario as I know.

The reason you want to convert to CNY first is because you want to LOCK in a good rate NOW.

If you want to minimise cost, you don't want to over convert. Because when you convert from CNY back to MYR after you come back from your trip, you incur another round of conversion fees. Itu saje. It's a risk you have to take.

I just link wise card to alipay. Didn't really bother to convert to CNY. But when I went few months back, not much fluctuations in the rate.

Yes. The 3% charged by alipay.

Yes. As long the transaction is made through international bank cards (not issued in China ones), and the transaction amount exceeds 200 CNY, Alipay themselves will charge 3% of the entire transaction amount.

Same goes to WeChat Pay.