My vehicle’s infotainment system apparently doesn’t sync to the paired phone. When the phone’s screen is projected via Android Auto (or Apple CarPlay), I see the time from the phone. Otherwise, the infotainment system’s time is syncing to something else. I expect similar to @mwgardiner’s experience, it’s the internal navigation system offered by the manufacturer to which I do not subscribe.
Mine was off by exactly an hour because I had yet to hunt down the setting for turning off Daylight Savings Time (since corrected).
Tested this as well and it’s working as expected for me, which I appreciate doesn’t help you. 
Given these reports, I changed my focus to a possible issue with running dual SIMs or, perhaps, the Helium Mobile eSIM specifically.
I first turned off dual SIM functionality (not an ideal solution). Then, I tested running both the Mobi pSIM and Helium eSIM is single SIM mode. Both worked as expected. Next, to see if dual SIM could be stabilized.
There is a new Android 14 setting “Switch mobile data automatically” when running dual SIMs. I reenabled dual SIM but turned that setting off for both SIMs. Things remained stable.
This configuration, however, is also not ideal because that setting, which allows for use of the SIM not active for data when it has better availability than the SIM active for data also controls the ability to use voice and data simultaneously when the SIMs for voice and data are different and backup calling. In Android 13, these were two discrete settings.
Backup calling is a Pixel feature allowing for VoIP calls using the active SIM for data when the SIM being used for voice has no signal. Think of it as WiFi calling over the active data SIM. Apple actually calls the equivalent iPhone feature WiFi calling even when using a different SIM enabled for data rather than actually using WiFi. Dual SIM phones allow for multiple SIMs to be active for voice and text but, generally, only one SIM at a time may be active for data. Backup calling is most useful for international travel as one’s U.S. service can be used for voice and text messaging over a local (in country) SIM active for data while out, about and away from WiFi.
Here’s the current state of affairs. I’ve reenabled “Switch mobile data automatically” for the Mobi pSIM but not the Helium eSIM. I’ve also disabled WiFi calling and Vo5G (more technically referred to as VoNR) on the Helium eSIM and 2G on both the Mobi pSIM and Helium eSIM. So far, this configuration is stable with coverage switching between 5G and LTE as expected on either SIM active for data at the time.
As an aside, I’m losing nothing by disabling calling features on the Helium eSIM as both calling and text messaging are disabled at the network level. Talk and text is available on Helium at no extra cost but requires a separate Helium pSIM. The Helium eSIM provides 30 GB of high speed data per month on T-Mobile’s network but also is intended to offload to Helium’s network of hotspot devices (currently available nowhere near me). I guess Helium/T-Mobile do not want voice running over those hotspot devices. Bottom line, I get 30 GB per month on T-Mobile’s network from Helium for $5/month while keeping my primary service (unlimited talk and text plus 1 GB of data) on Mobi for roughly $10 per month.
If I were to travel internationally, I’d activate a local (in country) eSIM and temporarily deactivate the Helium eSIM. Deactivating an eSIM on a phone does not, in and of itself, deactivate service.
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