There's something that might help. It's called the split-key method. No idea if it's safe. It's used in VanitySearch: https://github.com/JeanLucPons/VanitySearch

I used that in a vanity npub generator I put together. I call it noclvag. You can find it here: https://njump.me/nevent1qyt8wumn8ghj7ct4w35zumn0wd68yvfwvdhk6tcpr4mhxue69uhhyetvv9ujumt4w35ku7thv9kxcet59e3k7mf0qy88wumn8ghj7mn0wvhxcmmv9uq3zamnwvaz7tmwdaehgu3wwa5kuef0qyg8wumn8ghj7mn0wd68ytnddakj7qg4waehxw309aex2mrp0yhxgctdw4eju6t09uq35amnwvaz7tmzdaehgu3wd3jkxar4wf5kv7fwdejhgtcpr9mhxue69uhhyetvv9ujuumwdae8gtnnda3kjctv9uqzqd6mt9jq60s34za2zkmrshtv6srjsswjd2hk4f5q9act54qunge77nxq9p