Similar question asked previously, you might take a look there.
I would recommend you either
CoinGate or
BTCPayServer. The latter can be self-hosted, but
third-party hosting is also available. Both of these solutions support SegWit and the Lightning Network so you and your users will save on the transaction fees. I haven't heard of eliopay, so I can't tell you anything about it.
I think CoinGate would be easy for you. Seems it also support multiple coins. Anyway you have to use third part wallet in order to receive payments from customers. You might also use
coinbase API, as far as I know they do not require any fee for receive payment, but you might need KYC verification to avoid further problem. (Coinbase isn't recommended).