You don't have to keep everything in one wallet just because it's more convenient. In fact, you shouldn't do that. Increased convenience usually means a decrease in security. That's exactly what you get with unsafe wallets like Guarda and the like.
I agree with dkbit98 above regarding Cake wallet for storing altcoins. It also have a built-in exchange but I don't think the software supports fiat. I am not a fan of Unstoppable wallet, though.
Keep your bitcoin separate from everything else. Check out Electrum or Sparrow Wallet.
Your ethereum and ERC-20 tokens can go to MetaMask.
With hot wallets, you have to be sure your device is clean. Regardless which wallet you use, if your computer/mobile is infected with malware, you increase the possibility of losing your crypto. Only move bigger sums to hot wallets if you are confident that your device is safe. Although, keeping your money in a centralized exchange is far from a good alternative.