Can't download software ScanSnap IX1500 as I have MacOS Sequoia 15.2

Check out this other post where the user mentioned using the driver for a different model ScanSnap. It involved Sonoma instead of Sequoia, but maybe it will still work. It was also a slightly different model 1500 scanner. Make sure to read my post in that thread as well since the link to the driver in that thread is dead so you may need to look for the more recent driver version.

ScanSnap S1500 On MacOS 14.6.1 - Apple Community

I know in the past that using a different driver like this did allow an older unsupported scanner to work.

I think @Keith Barkley's suggestion for VueScan is probably the best long term solution if VueScan supports your scanner.

You should be able to install software just the same, unless your drivers are trying to install inside the Mac protected volume.

Where are you getting the software from and what happens when you try to install it?

I suggest getting VueScan from Hamrick, anyway:

https://www.hamrick.com/vuescan/fujitsu_scansnap_ix1500.html#technical-information

VueScan does support it, I actually linked to the page that says it does.