I also asked myself this question and tried it out straight away: I am now "covered" until August 2022. So the answer to your question: Yes, it works! :-)

I bought two and put them in right away (once yesterday, once today). It went without a hitch. Next payment is due in 2022 (as my subscription was already running in December 2022).

https://helpx.adobe.com/download-i...
If your payment plan is Annual plan, paid monthly, Adobe stops charging your credit card after you redeem the code. After the redemption code subscription term expires, Adobe resumes charging your credit card.
If your payment plan is Annual plan, prepaid, the redemption code term is added to the end of the paid subscription term.

So it seems it depends on how your subscription is paid (monthly or annually).
I've renewed 1x (for an annual subscription) and am happy with what I have. I'm not interested in another renewal at the moment, I don't want to be greedy.