Hip Thrusts HR

Just looking for some advice on other people’s experiences with heavy lifting and their heart rate? I feel like I’ve plateaued because I’m scared of my heart rate going too high. I currently do between 89-94kg hip thrusts on the smith machine, however I used to manage 99kg no problem. I’ve dropped down, as I’ve noticed that even on the 94kg my HR spikes go around 184bpm for a second or two before dropping back down. It never goes below 125bpm between sets.

I don’t feel like I’m going to faint or anything, I just feel like I’ve lifted some heavy weights.

Is my HR likely to go too high if I continue to progressive overload? I’m not sure why mine sits higher than the average.

My resting heart rate varies between 70-90bpm.
I’ve been aware of my heart for roughly 2 years now, likely partial health anxiety when it comes to it for sure.

I just want to be able to continue to progress! Am I just really unfit? 😅🤣

Any advice or experiences would be helpful!
Thanks!!