From the release notes, it certainly seems minor / backwards compatible.
> 5.0 is not a disruptive release, and everything you know is still applicable. While TypeScript 5.0 includes correctness changes and some deprecations for infrequently-used options, we believe most developers will have an upgrade experience similar to previous releases.
It has one of the largest internal rewrites in TS history (namespaces to ESM switch), so it's somewhat incredible its backwards-incompatibilities list is mostly minor/edge-cases.
(Which is to say that Typescript probably couldn't use semver if it wanted to because it has some extreme views on backwards compatibility, but also that this amount of codebase churn is absolutely semver breaking in the strictest semver senses even if it is mostly backwards compatible.)
> 5.0 is not a disruptive release, and everything you know is still applicable. While TypeScript 5.0 includes correctness changes and some deprecations for infrequently-used options, we believe most developers will have an upgrade experience similar to previous releases.