hi , @macbeth15 

So if i understand u correctly . You have get E-Sim to your Galaxy Watch 4 . And first everything worked , but not recieving sms . And then you removed the e-sim connection and re-connected the E-Sim again , and now you cant either send or receive sms . 
 

Is their any systemupdate you can do , with connection from your phone ?

https://www.samsung.com/us/support/troubleshooting/TSG01003245/

Best regards F 

Yes, this is correct. My watch’s software is up to date. Do you know if Tre supports text messages on the smartwatch plan at all without having an ongoing data connect on to sync with the phone?

Hi ,  it should support text messages with e-sim . 

https://www.lifewire.com/receive-text-messages-on-samsung-galaxy-watch-5217923

I also found this and translated it to English. 
 

So if u have 4G / LTE model of Watch .  The phone need connection to it anyway. Maybee not the solution , but good to know . 

https://eu.community.samsung.com/t5/samsung-lounge/samsung-galaxy-watch-4-lte/m-p/4647980#M3354

It is now confirmed both from the operator and Samsung. The watch cannot send SMS if it has no contact with the phone in the various ways. Communication with the phone must be via BT or wifi for it to work, if those communication methods are not available the watch uses the internet (LTE) to contact the phone and in turn send SMS. If the phone is switched off or is set to airplane mode, text messages via the watch will not work. The esim installed on the watch is only an addition to the esim of the phone and is dependent on each other and cannot be distinguished. It might go without saying, but it wasn't for me. For those who have encountered the same dilemma, the answer is here.

If it not starting to work , u have Samsung support you can get with your Watch. 

https://www.samsung.com/us/support/mobile/wearables/smartwatches/galaxy-watch-4/

Best regards F