One caution about changing the captive portal as described in various de-Googling guides is you can shoot yourself in the foot, as ime the entire cellular (and even Wi-Fi) connection can fail to work if the captive portal domain doesn't return the correct 204 status code (which can happen when some independent servers randomly fail or their HTTPS cert isn't renewed), which becomes frustrating to troubleshoot as the issue can be intermittent.
Additionally the guide I've seen referenced the most (from Reddit, which a popular Youtube video is directly based upon and which this article covers the main points of) suggests an outdated HTTPS URL which no longer works. I'd imagine many are just blindly copying adb settings and encountering problems (the burden of which often falls onto LineageOS community support as people spend time trying to identify an issue).
Additionally the guide I've seen referenced the most (from Reddit, which a popular Youtube video is directly based upon and which this article covers the main points of) suggests an outdated HTTPS URL which no longer works. I'd imagine many are just blindly copying adb settings and encountering problems (the burden of which often falls onto LineageOS community support as people spend time trying to identify an issue).