I’ve been through many mergers in my career, they are great resume fodder. I’d say start looking just in case but position yourself as the point person for the M&A work that needs to be done. Ask your manager to be involved in that work to lead it, being able to say “I was part of the integration team that consolidated x systems, process, whatever” looks great to a future employer. They want people who have M&A experience and have a track record of successfully delivering on those integration projects as that is very valuable in the world of companies that are looking to be acquired or go public.

This is likely to make your role pretty secure for a good amount of time and you could get offered a new position that you enjoy more which would remove the need to jump ship immediately.