Indeed, the Chrome User Experience (CrUX) report, does not currently measure SPA navigations (no new LCP), nor does it slice full page lifecycle metrics (like INP or CLS) on SPA routes. (Thus, neither does pagespeed insights etc)
However, the performance data that powers those metrics are exposed to the web via Performance APIs such that you are able to gather your own field data. So, if it is important for you to understand your field metrics and you are already collecting this via some RUM data provider (or rolling your own simple collection, perhaps using web-vitals.js) -- it is possible, perhaps even relatively easy, to slice on SPA routes yourself.
There are several projects underway to do what you ask for: automatic soft-navigation detection
, LCP events post soft-navigation, and INP/CLS slicing based on route change. I would not expect such data to be available to CrUX in any predictable time frame, however, you can test these features in Chrome
, either locally just by enabling experimental-web-platform features, or in the field via Origin Trial
on Chrome right now (ending very soon, perhaps will be extended...).