Even Binanace has a 2m sat upper limit on transactions AND it doesn't allow transfers to two specific wallets, Muun and Breez which are both non-custodial wallets that allow you to hold your own keys and use some fancy behind the scenes tricks to be Lightning wallets on a phone.
The reality is that they put a 2m limit on probably because the rest of the network isn't reliable above that and I can already imagine that running the liquidity on their node is a bit of a pain. The restriction on Breez and Muun is likely due to the delays which occur when they do zero confirmation channel opening (and you trust them for a few minutes while main chain transactions occur).
Thanks for the comment I'll take you up on that voice chat later when we've both got higher energy levels and I actually commit to writing a post dedicated to LN. Might be a hwile.