I will backup Darth's recommendation on coinos.io it is very quick custodian lighting wallet.

You might also find this post interesting https://stacker.news/items/548942

It is several months old and some data is out of date (example Mutiny).
  

Wumbo

But if somebody wants to pay me or add them and they need to download it within 2 minutes to run the app.

coinos.io or walletano.com - not even need to install anything, no KYC, no bullshit.

But then after that must climb the ladder to a self-custodial one...

Read more in my guides, you have all you need there.

bitcoin

Does kyc really matter if I don't plan on having an exit ramp

Recongraves

> But if somebody wants to pay me or add them and they need to download it within 2 minutes to run the app.

coinos.io or walletano.com - not even need to install anything, no KYC, no bullshit.
But then after that must climb the ladder to a self-custodial one...
Read more in my guides, you have all you need there.