I'm new to Ledger.

As a software engineer, I'd like to write my own app (for my own personal use) that is sort of like a more basic version of Ledger Live.

I want to show my balances on my own private dashboard on a website that I'm building for myself.

I want this website to show output like:

{
  BTC: 0.1,
  ETH: 1,
  NEAR: 20
}

where each ticker shows the total (sum) of all tokens that my Ledger "holds".

Since Bitcoin, Ethereum, and other blockchains are all public, I figured I'd easily be able to look up my wallets' balances via the public wallet addresses.

But now my understanding is that my Ledger's public wallet addresses for each blockchain change after transactions.

So how can I accomplish my goal?

Again, I want a simple sum of the tokens as shown in the JSON above.

And I want that sum to be retrievable periodically automatically without me needing to log in on my Ledger.

Thanks!

P.S. I found Is it possible to use xpub address to monitor balance from previously generated addresses? and How to know balance in Ledger Nano S?

But when I go to Ledger Live > Accounts > Bitcoin > wrench icon > Advanced and grab my "xpub" string and go browse it at https://www.blockchain.com/btc/xpub/xxxx, I see 20 wallet addresses (split across 4 pages) with 0 transactions each. So it seems like these are future wallets instead of the ones that my Ledger has used so far.

I'm new to Ledger.

As a software engineer, I'd like to write my own app (for my own personal use) that is sort of like a more basic version of Ledger Live.

I want to show my balances on my own private Google Sheet that I'm building for myself.

I want to use Apps Scripts to fetch totals from all of the relevant blockchains (ideally via a simple, free API) in a format like:

{
  BTC: 0.1,
  ETH: 1,
  NEAR: 20
}

where each ticker shows the total (sum) of all tokens that my Ledger "holds".

Since Bitcoin, Ethereum, and other blockchains are all public, I figured I'd easily be able to look up my wallets' balances via the public wallet addresses.

But now my understanding is that my Ledger's public wallet addresses for each blockchain change after transactions.

So how can I accomplish my goal?

Again, I want a simple sum of the tokens as shown in the JSON above.

And I want that sum to be retrievable periodically automatically without me needing to log in on my Ledger.

Thanks!

P.S. I found Is it possible to use xpub address to monitor balance from previously generated addresses? and How to know balance in Ledger Nano S?

But when I go to Ledger Live > Accounts > Bitcoin > wrench icon > Advanced and grab my "xpub" string and go browse it at https://www.blockchain.com/btc/xpub/xxxx, I see 20 wallet addresses (split across 4 pages) with 0 transactions each. So it seems like these are future wallets instead of the ones that my Ledger has used so far.