So far you refer to PoW, phone CPU is too weak to mine any coin. Better forget about it and get yourself strong miners like ASICs and graphic cards.
I've figured that there's not a single coin which you can mine on a smartphone for profit. Maybe PoS coins with "cold staking" features are worth it? Given that a phone's CPU is still not as powerful as the one used in computers, it'll take double the effort to make some profit "on the go". Even "Cuckoo Cycle" coins like aeternity are not as easy to mine on a smartphone as I've thought they would be. I hope that as mobile hardware improves over time, it'll be easier for people to mine cryptocurrencies for profit. It's much more convenient to do so on a smartphone than a computer due to its extreme portability. The only thing that's close to this is a SBC like the Raspberry Pi. But even this is not enough to stay ahead in the mining competition.
All in all, I appreciate your recommendations. I've been mining Monero and Ethereum with my PC's graphic cards, and the results have been great so far. I wanted something more mobile where I could mine wherever I go, instead of having a bulky mining rig that's stationary. Guess I have to wait until smartphones become comparable to everyday computers in terms of processing power. If that day comes, expect crypto to become much more decentralized than what it is right now.