That icon doesn’t mean there’s no internet, it means the app’s network access was blocked through the app info page. Hold on the app, click on app info, then network usage, and there you’ll see it,
Now, for @derives, I suspect this may be the fact that in custom ROMs, the motorolas (g32, g42, g52, I have no idea about the other ones supported by LOS) have broken 464XLAT, it’s a transition scheme for networks that are IPv6-only, to provide IPv4 connectivity. It’s basically NAT64 + DNS64, but with CLAT, which converts anything that would be trying to connect through an IPv4 literal (instead of using DNS to fetch the IP). It could also be a broken APN setting in general. I would try going in Settings → Network and internet → SIMs → Access point names and resetting them, or if that doesn’t work, find the ones for your carrier.
If it is 464XLAT, you could do the sad thing of enabling IPv4-only mode in the APN, and then saving. (Make sure to.)
464XLAT issue from the LineageOS side: 464XLAT is broken, CLAT doesn't start up (#7190) · Issues · LineageOS / issues / android · GitLab