Gatwick to Finsbury Park Station - Sat Sept. 30, 2023 - 10:30 am

I’m arriving from the Philippines and will be activating my 3-month Eurail pass on Sat. Sept 30 when I arrive.  I was planning on taking Thameslink to Finsbury Park Station using the pass, but I am encountering conflicting information from multiple sources that is made more complicated by a strike and “Planned Industrial Action!” on Sept. 30.  The Eurail site is showing “EXP” is available from Gatwick to Finsbury.  I think “EXP” is the Thameslink, but I’m not sure as Google Maps shows Thameslink and Gatwick Express are different. Google is showing no Thameslink service on this route on Sept 30.  National Railway is still selling tickets for this route, but it is via Southern Services to Victoria and then tube to Finsbury (so I take it the Thameslink is not operational on this route Sep 30?).   I think I can use the Eurail pass on Southern service from Gatwick to Victoria, but Eurail site is showing “EXP” connects Victoria and Gatwick.  This is all very confusing and before I “wing it” when I arrive, I was hoping for some useful suggestions here.   Thank you in advance for your help.