Why did it stall?
We find lifts that have stopped improving, check the trend isn't just noise, and look at what changed around the time progress stopped. You get a verdict in plain English and one thing to try next.
Why: weekly chest sets went from 12 to 18 while your top-set RPE climbed from 8 to 9.5. Fatigue is probably hiding strength you've already built.
Try next: one lighter week, then 3 back-off sets instead of 5 for four weeks.
Likely 9 sessions over 7 weeks, low noise