At the risk of bringing the world raining down on my head, I don’t use the LMIC for timing of send - you don’t have to initialise or maintain the send job, you can command a send when you require.
So I have an Arduino that runs through a series of 8 second sleep cycles and when it has completed, does a data collection, sets a ‘stay awake’ flag, commands a send, resets the flag when the send has completed and then goes to sleep.
The LMIC uses a faux scheduler to know when to open the RX1 & RX2 windows - so I give it free rein without any other ‘tasks’ running during the send & potential receive cycle. But I manage the rest of it’s sorry existence. Given the number of these scattered around me and out in the world as simple canary & temp/humidity devices that just keep on trucking, I’m very unlikely to be persuaded that this is a bad thing - I’ve checked, no puppies were hurt in the process of coding them.