Imho the payment options are still lacking.
#1 Stripe
To me, they're simply a lousy payment provider, and not suprisingly, as I live in the jungles of central Europe, they've refused to accept my debit card payment. This only happens with Stripe, ever.
https://docs.stripe.com/disputes/prevention/advanced-fraud-detection
Their docs pretty much confirm what I've been suspecting all along: They have a crappy AI model of human behavior and will push everyone under the bus who doesn't live up to what a standard human should be doing. Then they'll go ahead, boast with how many millions of "fraudulent" payments they've prevented and use those stats to promote their "services" further.
Is there any chance you can turn their "advanced" fraud detection off (provided you're using it) and see how it goes? I'd assume that their fraud detection is tuned towards shops where a single case of credit card fraud can be very damaging, and when you're selling Ferraris, it probably makes sense. But if I stole a credit card, using it to pay for search would be the last thing that comes to mind, and given all their false positives, you simply might be better off without it.
#2 Paypal
It's great that you're offering Paypal (I've used it for now), but it seems like you're charging 5.5-10% extra for any payment handled via Paypal (which includes SEPA). Add to that the extortionate, mandatory exchange rate charged by Paypal, and you're at 10-15% extra costs for anyone who doesn't have USD in their Paypal accounts. Fine to pay for a few months, but less than ideal for long-term members.
In the long run, maybe opening a SEPA account in Europe would be an option? Then 740 million potential Kagi customers could wire their money for free, and you'd simply incur a small fee to cover the costs of handling the account.