It seems you can't trade using the app from binance, and the a from coinbase only allows buying and selling from an account for limited crypto currencies.
Can anyone recommend a good safe and reliable altcoin trading app from a reputable brand (i.e. not by a random independent developer)?
what dou you mean you cant trade using the app from binance? It didn't work on your device ? Well as far as i know binance still fine actually and you can still trade with different altcoin. Probably you installed a wrong application mate. Try to search on your playstore to see the real one not on google because there are some fake apps.