Yes, you are correct, the program files (LR, PS, etc.) should go on the operating system (Win 10 drive C: ). Your Lightroom Catalog and preview files should go on the second SSD along with the Lightroom Cache (recommended more than 20GB). Depending on how big your LR catalog and preview file folders are, you may run out of space on a 250 GB SSD since you should leave about 2/3 to 3/4 of the SSD free for OS breathing room. You can set the Cache size and location in the LR menu: Edit > Preferences > Performance tab about 1/3 of the way down.
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