One more thing. If you are going to build your own wallet, you're going to need to choose an implementation -- LDK, LND, or CLN, basically, unless you want to wade into the world APIs and sidechains with Breez or Strike or other centralized players. I strongly recommend you talk to as many DIFFERENT experienced practitioners in Lightning as you possibly can before you decide how you want to build it. There are a lot of opinions out there, and you'll be best hearing the widest variety possible before making a plunge.