How do I make sure that the backlinks that I am building from different websites, stay live permanently?

Hi everyone. I am a newbie to SEO (it's been 6 months doing full-time), have joined an ed-tech startup, and now doing everything that there is in SEO, but primarily focused on link building. I have now built around 20 good-quality (in my pov) backlinks to our website, both with the help of brokers and directly contacting the backlinking websites. However, the concern that I am facing now is what happens if any of these website owners or brokers decide to remove my link from their blog and give it to someone who bids a higher price. Have you ever faced a situation or a concern like this? If yes how do you make sure that it doesn't happen? Thanks in advance.