I also did respond to your other post 😊 Apple typically supports products for seven years after they are discontinued. The Apple Watch Series 6 likely has a few more years before it is discontinued. However, you can also consider purchasing a new Watch, if you don’t want to put more money into your old Watch.
If the Blood Oxygen it’s important to you, then you should look into a medically approved Blood Oxygen device. Blood Oxygen app measurements are not intended for medical use. Also, the feature is disabled, though still there. If Apple does settle the dispute, I would assume they would try to bring the feature back.
Thanks for your prompt and kind replies, have a wonderful day.