UX is great, not much I can complain about! And that doesn't happen often.

One thing worth thinking about is the terminology. "Donate" and "tip" are words used more for just sending little bit of leftover money. In the value4value model I think it makes sense to switch to just "Send sats" instead, and highlighting that it's a good idea to reward for the value that you have received. According to Adam Curry ("the podfather"), just this small change in terminology results in people sending 4x more money (unfortunately I don't have exact quote).

It may be worth hosting the .js somewhere on CDN, but I guess you would have to be careful about security implications.

You can just try all the widgets you see on https://widgets.twentyuno.net. If you want to see some realworld-usecases, here are some random examples:

I know it’s not the easiest thing, but the LNMe project (https://github.com/bumi/lnme) can connect to any node, and host on your own domain, with the node behind TOR.

I wonder if it can be much easier than that.

Ln-address providers should be integrated into wallets allowing users to get an address easily.

With different limits like max amount of donation, fees, etc.