Not surprised.
Too many Trump voters sit home when Trump himself is not on the ballot. It's been an ongoing problem since 2018. Democrats, meanwhile, get out there for midterm and special elections.
This has been an ongoing problem for MAGA since 2018. Even the GOP wins in Florida today were tarnished by much smaller margins of victory than Trump enjoyed in November.
This needs to be rectified before November '26. If Trump loses the House, his MAGA agenda is pretty much over. He'll spend the final two years of his presidency fighting off impeachment hearings and special investigations.