Crashes and playback issues on 1.75 hour documentary feature seq from Premiere production

Hi all, 

I've been working on this film since 2017. 2 years ago I converted it to Productions because it was getting very slow and difficult to open up timelines and work. That seemed to help performance for a while but now that I have finally stitched the entire rough cut together, it is bogging down, beachballing and crashing. This happens all over the timeline, not in one particular spot and I find the crash happens most consistently when trying to redraw the timeline while resizing the tracks to do audio edits. I'm working on a iMac Pro 8 core 3.2ghz with 32GB of RAM. Using OS 11.7.1 Big Sur with Premiere v22.6.3. My scratch disk is an OWC 24TB thunderbay Raid 0 using Thunderbolt 3. All camera original footage has been proxied to ProRes proxy resolution, all video I source for achival is also converted to prores proxy. All audio is converted to AIFF or WAV regardless of where it came from. I even convert all the temp stock footage I download into Prores proxy at 1920x1080. The timeline resolution is 1920x1080 and video previews are set as prores proxy. I had some nested sequences in the project but have exported those at ProRes Proxy MOVs and cut them back in. I had 3 instances of motion templates using the waveform generator but have also converted those to ProRes proxy and cut them back in. It is very expensive to upgrade the RAM on my system so I need to know if that is really useful at this point. I know plenty of people who can cut feature films in Premiere and are able to playback without issue. I feel like I'm doing as much as I can to make this easier on Premiere but it continually falls on its face. Any help or guidance is appreciated thank you!