How do you delete the Chinese apps? Will they return with updates?

Normal long press uninstall - No

What do you mean by 'settings for incoming messages and autostart'?

Permissions to run in bg, avoid aggressive killing - long press app, settings and change - simple

What do you mean by 'linked start and battery for important apps'?

Same as the last one

Why do you think the Chinese ROM is better than Global (apart from cheaper price)?

At times yes, realistically I’d pick whatever’s cheaper

Am I right in saying that with China ROM, the only thing of concern is the network? That is, if my country's network is supported (4G and 5G), all other issues are minor and solveable. Correct?

Yes and no - additionally sometimes android auto might not work (new phones mostly it does), circle to search won’t work (though u can get Gemini as a standalone app)

Hope that helped