See this page for ongoing access to your data if you do not renew the subscription. You can still enter new transactions manually, except for the Starter Edition which becomes read only and is limited.
If you don't renew a subscription about 25% of your screen will be taken up with a reminder to renew.
https://www.quicken.com/support/what-quicken-data-access-guarantee
See, https://www.quicken.com/support/quicken-subscription-membership-faqs Under...Why am I seeing an expiration banner?
There was this thread, Expiration-Vote , but it has been closed
If you have or can find a copy of Quicken 2017, I think you can go back to the previous version with no nag screens.