Two things...
1) is it that QB will be entirely discontinued, or just that certain features will be disabled. (i.e. payroll, bank feeds, email invoices, that kind of stuff). In this scenario, (presumably you have QB 2019) you can continue to use QB without those features. It'll still work just fine for accounting purposes. And you can find workarounds for many of the limitations - for example, you can't email invoices directly from QB, but you can create a PDF of the invoice that you can email outside QB.
2) if you have one of the Plus subscription, then yes, that's basically ending. I'm getting mixed messages about whether Pro Plus exists at all this year (was 500/year last year), but Premier Plus (800/year) and Enterprise (1300/year or more) are still available.
If you do have a pre-2022 permanent license for QB, that's like gold in my mind. Done properly, you can keep that running forever and it is the best combination of price and features you'll ever find.