Beside it, never instead
The price in your own currency stays the leading one and is not touched. The sats amount sits next to it or under it, set smaller.
Next to your price stands the same amount in sats or bitcoin, smaller, in the font and colour your theme already uses. You keep charging in your own currency.
The price in your own currency stays the leading one and is not touched. The sats amount sits next to it or under it, set smaller.
Product pages, collections, the cart. Including the prices that appear after a variant switch without the page reloading.
Unit, symbol and position sit on the block in the theme editor. Everything else the second price inherits from your theme.