Luckily there are still other options out there. ZeroSSL is one I quite like: Free ACME-based certificates just like LetsEncrypt, without the rate limits, and does have paid plans if you need support. It also has better legacy client compatibility than LetsEncrypt as far as I know.
I hope that ZeroSSL has improved their policies and procedures in the past years so they're more safe and robust. Four and a half years ago, there were some significant oversights in certificate lifecycle management, TOS, and handling of key material, which needed external parties to notify them of those issues before they fixed them. To me that was an indication of limited awareness of WebPKI and security principles.
