Investment depends on mining equipment. You can mine both Doge & ETH with GPU. You probably know that GPUs are of very high price these days and so does the other mining hardware. You can import an ASIC miner for scrypt algorithm as Doge is scrypt algorithm crypto.
And regarding the profitability, it is certainly profitable these days as the price of the crypto is so high now. However, the difficulty has also increased.
To check the profitability, you can try with some online calculator by putting your device model-
https://www.nicehash.com/profitability-calculator