Catalog browser thumbnail rendering issue

Greetings All, thanks in advance for any suggestions on this issue I'm having. I've combed through the forums here for an answer and tried several of the things I felt were related to what I have going on but to no avail.

So, to lay the groundwork, my Mac's specs are as follows:

- Mac Pro (Early 2009) upgraded to 3.46 GHz 6-Core Xeon
- 48 GB of ram
- Radeon RX 580 8 GB video card
- Three SSD drives, one for OS, one for Catalogs, one for caches, VMs, & misc
- One 4TB WD Blue spinning disk for working files, images, etc.
- macOS Mojave 10.14.6
- Capture One 20 v.13.1.3.9

The Catalog SSD's w/r averages around 460 MB/s & the images drive's w/r averages around 146 MB/s. I primarily do graphic design work & photography and haven't felt hampered by the machine's speed with most of what I do. I've been an Adobe software user since the early 90s and Lightroom user since the Beta days (.

My C1P master catalog currently has just over 65,500 referenced images and comes in at 76.48 GB. I use a pair of Dell 24" UltraSharp Monitors so my preview size is set 1920 which matches their resolution pretty well, and I also made sure that all my RAW files (a mix of supported cameras) have external XMP metadata files that were generated from my master original Lightroom Catalog.

I decided to make a move over to Capture One a few months back for the better RAW handling & color, and while I really appreciate the quality of the image rendering, unfortunately, the speed of the catalog system leaves quite a bit to be desired.

Even though all of the image previews were rendered out when I first imported my images (which took around three solid days of rendering), scrolling through the browser usually shows 2/3s of the thumbnails appearing as dotted outlined squares and then subsequently rendering in the thumbnails slowly. This behavior happens sporadically throughout the catalog, with some sections being worse than others and not specific to one RAW file type over another. Having to render thumbnails also happens if I scroll back through the catalog the opposite way, but in different sections, than it did on the first scroll.

I have noticed that if I narrow down the image count in the browser by clicking on a folder of images in the library panel, all the thumbnails show up instantaneously.

Beyond the thumbnail rendering issue, all the image tools work snappy and work as expected, but unfortunately, this type of behavior makes it very difficult to do any kind of DAM work without becoming somewhat frustrated, especially since the previous Lightroom catalog appears blistering fast compared to the new Capture One catalog.

So with all that said, I'm left thinking this is a catalog size issue, but I figured I'd throw this out to the group before submitting a request for tech support. I'd rather not go to a situation like the bad old days of Lightroom a few versions back, using separate catalogs for each year, but due to the fact that I'm starting to camera scan my film archive I only see the image count going up so this situation has the potential to become worse and that might be my only solution.

Again, thanks in advance for any suggestions to remedy this catalog browser thumbnail rendering issue.