Thanks all, I decided to give mempool a try and it seems to be meeting my needs so far.

I want to be able to run address queries (balance, tx count, etc.) similar to the API provided by Block Explorer, blockchain.info, Blockcypher, etc. For performance reasons I want to run my own node & server and not depend on someone else's API (most/all of which cost money for making a large number of requests, or rate limit their free requests).

The Bitcoin Core RPC / REST API does not support general address queries, only queries against addresses in your own wallet and then some general blockchain status info on top of that.

Blockcypher Explorer publishes open sources for the web front end, but apparently not for the back end server that does the actual address indexing & search: https://github.com/blockcypher/explorer

I found "iquidus explorer" but this comment says it is too slow to practically use with Bitcoin:
https://github.com/iquidus/explorer/issues/452

I found several other projects that work with Ethereum, Cardano, and other coins but nothing for Bitcoin. Any others you know of that work with Bitcoin?

Thanks.