ThinkPad P15s has Thunderbolt 3. Thunderbolt 3 on PCs doesn’t guarantee that two displays are supported from a Thunderbolt port, unlike Thunderbolt 4 which requires support for two displays from a Thunderbolt port.
The tech specs say the USB-C port used for charging also supports a display so you can try that with one of of the CAC-1510-A.
The tech specs for the ThinkPad P15s don’t say how many displays are supported from the Thunderbolt port. They also don’t say what GPU (Nvidia or Intel) is controlling each display output (built-in, USB-C, Thunderbolt, HDMI). Connect a display to each port, use the Device Manager (view by connection type), to find each display and see what GPU the display is connected to. Let us know the results.
If you find that the CSV-1580 Thunderbolt 4 hub doesn’t allow connecting two displays using the two CAC-1510-A adapters and you can’t use the Thunderbolt and USB-C port simultaneously, then you might try using the HDMI port for one of the displays using a CAC-1332, CAC-1333, or CAC-1336. I prefer the CAC-1332 because it also allows USB 2.0 (not useful in your case because you’re not connecting a USB-C display). The CAC-1333 doesn’t support USB 2.0 but it may be more convenient because it doesn’t require an extra power connection. Both the CAC-1332 and CAC-1333 are limited to ≤ 4096 width but that’s good enough for your 2560×1600 displays. Hopefully the CAC-1336 allows USB 2.0 connection and width > 4096.