I have an iMac 27” 2019 3.7 GHz Intel i5, with 32GB Ram, running OS Sequoia 15.7.4.
The website that I’m currently building is photo-heavy, strong on graphics and animation and has been functioning well under these conditions until the last OS upgrade (from OS 14.x to OS 15.x) where I noticed that only the Sitely app is daisy-wheeling whenever I save this project. It takes a long time waiting for this to pass, which is slowing down my progress.
What I’ve done so far…:
Closed all unnecessary apps.
Checked Activity Monitor to see what app is greedily eating ALL the Ram (only Sitely is top, using 1.14GB) - With all other background processes totalling 15GB (which should be pretty manageable with what I have).
I have occasionally have to log out of OS and rest (to reset the ram, I guess).
Apart from avoiding the temptation to SAVE this project so much, I’m not sure what else to do here… any thoughts?
What you are describing is exactly what I went through with Sitely on my 27" Retina 5K intel also with 32Gb, but one year older than yours. I found that after every macOS update my Mac would run like crap!!! So my Mac was stuck on macOS Ventura, with incremental updates… The more I updated Ventura the slower my machine became. Even with a power off/power on it would take nearly 2mins for me to get into macOS!
I know that Duncan & Team was constantly tweaking and refining for the older Macs, but in the end it was my hardware and Apple working their “end-of-life magic” on my Mac! They are in the courts for it slapped with a massive lawsuit - not only macOS, but also iOS!
For me the beachball was not only with Sitely, but with Affinity, with Apple Mail, with Safari and especially with Finder, etc, etc, etc…
I love Sitely so much that I invested in a new Mac Mini M4 and totally realised it was the hardware and it was like a night and day experience!!! Sitely is just really really fast! Even pulling down the footer on really heavy imaged pages is so fast!!! On my intel Mac it was 5cm move 10-15secs beachball on repeat.
Have you also tried emptying out the Publishing Cache to see if that helps? It’s under Sitely / Settings / Publishing Caches
In the end @jimiknits you might need to look into a hardware upgrade. For me it was the 5K retina display that was hard to let go off. But for most of the world the 1K, 2K displays are king! so I have adapted.
I did once empty all the publishing caches. This worked for a while, but as you build the project, the caches build too so it was back to it’s old bad behaviour again.
Given your experience of this, it leaves me with the dreaded conclusion that I may need a complete kit upgrade… groan! It’s up there with buying a new car and other “sh*t I hate having to do”!
So my Mac was stuck on macOS Ventura, with incremental updates… The more I updated Ventura the slower my machine became. Even with a power off/power on it would take nearly 2mins for me to get into macOS! 
It’s up there with buying a new car and other “sh*t I hate having to do”! 
