When you say "update" did you fully remove and reinstall Google Pay, or did you just move to the latest version of the Google Pay app?
Fully deleting the google pay app and reinstalling worked for me on s10+
problem is - background activity
when you update to Android 10, phone reset some settings by default
one of this settings is background activity of Google Pay
tap and hold on GooglePay
choose About it
turn on Background Activity
I agree this is deeply irritating and unexpected. I much prefer Google Pay.
HOWEVER - there is a workaround for your bank not supporting Samsung Pay, at least for those of you in the UK, and it has some handy additional benefits.
I have a Curve card, which is a physical card that allows you to add all your Mastercard and Visa cards (not Amex currently), and pay online or in-store (PIN or contactless), and 'map' the payment to whichever card you choose. This means you only need to carry one card, not multiple. The app keeps track of what you spent on what card as well, so you have a unified spending history.
If you forget to swap, for example you pay whilst mapped to your personal card and it should have been on our your company card, you can go "back in time" and swap the transaction to the correct card.
On top of that, it allows you to use credit cards where they wouldn't normally be allowed e.g. Costco, because the Curve card shows as a debit card aaaaaaaaaand (in the UK), you can add your Curve card to both Google Pay AND Samsung Pay :-D
Hey presto - suddenly your bank 'does' support Samsung Pay. (Actually, it's allowed me to also use my Tesco Mastercard on Google Pay - bonus!)
Plus (yes, there's more), Curve does not charge fees foreign transactions or ATM withdrawals made abroad (subject to T&CS). You can make purchases in foreign currency converted at the real exchange rate i.e. the rate at which banks exchange money, also known as the interbank rate or mid-market rate. (There are certain limits on the amount up to which you can make fee-free transactions or ATM withdrawals, after which charges will apply).
The basic/blue Curve card is absolutely free. I've been using mine for about 9 months now and I absolutely love it - wouldn't be without it.
If this sounds like something useful to you, use this link to sign up and you'll get £5 when you make your first transaction with your Curve card.
I have no affiliation with Curve other than being a very happy customer - hope this helps a few people :-D
It's Sad to say due to lack of support from Samsung even from online chat support I am reverting back to iPhone and getting myself iPhone 11 Pro 256Gb. I had Samsung 8,9 and then 10 was very please with 10 up till they decided to release a software that made my life a hell, Google Pay was the main reason for me to move away from S10+ sadly nobody wants to support Samsung Pay and by Google pay not working I just had to make that call. As we the society become more dependant on contactless payment and their mobile device it has to now become Samsung top priority to ensure a smooth OS and work very closely with the Android team to achieve that. For now goodbye Samsung will miss S10+