Do you try ever-so-rarely to just like send them a quick ping with something you know of interest to them or inside-jokey?
Like just let them know you understand if they don’t wish to respond and that you 100% respect the distance, but you might just rarely send them a little thing here or there that we maybe used to have fun texting each other with and that they can jump in any time they like or at the very least, if at that point they feel this way, to let you know once that they don’t want anymore.
If there’s radio silence you’re still in the clear and onwards/upwards