I second Hanley's recommendations.
For a fun anecdote, at the moment, I'm doing 8 sets of bench 4-5 times a week. That's as part of an RPE-based 5% fatigue drop from an 8 RPE... it only stops at 8 sets because rest periods start decreasing as desire to stop benching accumulates.
Quick update:
In 43 days my bench moved from
176 lbs 4x8 to 181,5 lbs 6x8. This rate of progress would probably make me a novice, right? If yes, why did LP with microloading not work anymore, even though the poundage I add per month is about the same as it was on microloading LP?
You probably weren't getting enough stimulus to make progress.