I commented this further down, but I think you are confused with this bit:

RCS limits attaments to 100mb! What the hell, why? I can, today, send 100mb over SMS/MMS, on Verizon, to other Verizon phones. RCS would be a step backward.

This is not true by any means. See here: www.verizon.com/support/knowledge-base-14641/

The maximum file size for picture/video messages depends upon the device software and device’s network capability. View the signal indicator on your phone to determine which signal is being received:

4G / 4GLTE = 1.2MB image / 3.5MB video

5G / 5G UWB = 1.2MB image / 3.5MB video

Using Verizon Messages = 100MB over Wi-Fi