If you downloaded and installed the Jan 2021 Epson ICA Scanner Driver v5.8.9, that should enable it for Apple's Image Capture. No other Epson downloads dating from Oct 2020 would be compatible with Big Sur, as it was not released until well into Nov.
In System Preferences > Printers & Scanners, right-click on the scanner entry and select Reset printing system… When you re-add the device, select the newly installed v700 ICA support. If there are any other controls on that Printers & Scanners panel, pay attention to them. At this point, you should be able to launch Apple's Image Capture and it should recognize the V700.
If this does not work, then your fall-back option is to trial VueScan Professional (as Epson suggests) as it can drive this scanner without any Epson software or drivers installed.