Blockgum is a Geth alternative as It supports HDWallet, which can generate billions of addresses. It uses Single Master Public and Private keys. No need to maintain Millions of Private keys. Backup once and you are good forever. Blockgum can read multiple chains ie Multichain Wallet Full Server side wallet solution. the https://blockgum.com
Why do you think that https://github.com/cosmos/cosmos-sdk is a good alternative to blockgum