Any text message I send on my Galaxy s20 Ultra to an iPhone user rarely go through and get stuck on pending status or fail all together. I had this same problem from time to time on my S10+ through Verizon. Seems to be a common problem based on multiple forums.
I rely on my messages to keep me connected at all times and want to ensure you can rely on your messages. Let's take a closer look into this. What message app is in use? Is this happening with multiple contacts or just one? Is this s regular text or a picture message?