Alternatives to Upsource for “review-per-commit” workflow?

We use Upsource for code review, but it is reaching end of life.

We use it as a "non-blocking code review"-tool, where reviews are created for all commits.
We use Trunk Based Development (ie. without branches) – so we need a tool that:

Discovers new commits and creates reviews.
Assign team members
Supports raising concerns or commenting with questions or feedback.
has an overview people can use to perform their review work (i.e. open reviews, concerns to handle, and other)

Most tools are based on Pull requests – that is NOT what we want as we work only on master/main(/trunk)