Hello,
It’s true that CoinPayments is no longer available in the United States.
You can use Bitcoin or Monero with your own full node, or with any full node that is compatible with one of these two technologies (Litecoin, Bitcoin cash, Dogecoin, etc), as described here: https://www.dashed-slug.net/howto-choose-between-available-wallet-adapters/
There is no Kraken or Coinbase integration for technical reasons.
There will not be any additinal support for ERC-20 tokens unfortunately. The only ERC-20 support is for a few select tokens via CoinPayments, and only if you are not based in one of the restricted countries.
In a few days or a couple of weeks tops, I will be releasing a Bitcoin Lightning adapter I have been developing, which is compatible with lnd. The advantage here is that you can have Layer1 and/or Layer2 bitcoin transactions without setting up a Bitcoin core full node which requires a lot of resources. This is because lnd can be installed with a light neutrino client which is based on bloom filters. More on that on the blog on the time of the release. If you follow the dashed-slug on facebook or twitter you won’t miss it.
Hope this helps. Please let me know if you have any more questions.
with regards