Having changed from LineageOS 17 to /e/ Version 1.5, I faced the problem, that my data connection is stuck at E(dge) though having 4G/LTE before.
I did have the same problem with LineageOS 16, but after the next nightly update, the problem was gone.
Now, I do not have the time to wait as the LeEco is still my dailly driver. So I checked several APN and network settings. But as the settings were identical to my old settings, nothing happened.
I tried to install google carrier app for network settings, played with IPV4/IPV6 settings, wiped cache, installed older /e/ versions but nothing changed.
I was close to give up hope and ejected the SIM card to put in in my backup phone. I do not know why, but I put it back to my LeEco and started it again for a last data transfer. And now 4G was available. Thats very odd, because I did not change anything except putting the SIM out and in again. The only difference was, that I put the SIM in the second place of the SIM tray.
Even GPS is working now. Yesterday, my phone was for serveral hours in my car and could not get any GPS signal