Use multiple browsers… Chromium for google services if you must, Tor for everything anonymous that does not require captcha, IceCat for any additional resource intensive tasks like video calls, and for the rest use free browser like Epiphany, Midori or Falkon.
But as you asked for Windows there is not many open source browsers so you have to blindly trust anyone like Edge, Opera, Chrome, Vivaldi, other chromium forks… If you choose to use these proprietary browsers you might want to use something overseas (in example if you are American use Yandex browser) instead local ones so the data they gather is less likely used against you, however it might be sold as less anonymized depending on origin, who knows. Also if you use a proprietary browser I would not do anything deeply personal or political or even visit forums like Lemmy.
Unless you get it because it is easy repair or need it for Ubuntu touch and do not want pine phone for some reason, I do not see the point. Ethical reasons they claim are debatable, as presented in articles. It is fine phone or not fair phone, and for premium cost.