I had certainly read what was described in Erel's post, but, being this post from 2018, I believed that a remedy for this limitation had been found in the meantime.
So, if I understand correctly, there is no other way to send an SMS from B4A than using an intent.
Nor is there probably the possibility to check immediately whether the SMS has been sent or not.
When sending emails with the SMTPExtras library vice versa you can use the sub Sub SMTPExtras1_MessageSent2(Success As Boolean, Tag As Object) and check if the sending was successful. Very comfortable and effective.
That of Google is therefore, in my opinion, a great limitation.