i want to use proxy vote but it says i need Transport Layer Security (TLS). do i have that?

For Mail,  port 465 is enforced TLS-wrapped and is generally used by Outlook users.

TLS security

iOS, iPadOS, and macOS support Transport Layer Security (TLS 1.0, TLS 1.1, TLS 1.2, TLS 1.3) and Datagram Transport Layer Security (DTLS). The TLS protocol supports both AES128 and AES256, and prefers cipher suites with forward secrecy. Internet apps such as Safari, Calendar, and Mail automatically use this protocol to enable an encrypted communication channel between the device and network services. High-level APIs (such as CFNetwork) make it easy for developers to adopt TLS in their apps, while low-level APIs (such as Network.framework) provide fine-grained control. CFNetwork disallows SSL 3, and apps that use WebKit (such as Safari) are prohibited from making an SSL 3 connection.

https://support.apple.com/guide/security/tls-security-sec100a75d12/web

macOS does have TLS support, yes.

If that's the ProxyVote website, the description there is definitely confusing.

An iPhone or iPad running iOS 12.2 and later, as well as a Mac running macOS 14.4 and later—this includes macOS Catalina, which is what you're running—includes support for TLSv1.3, which is the most current TLS standard available, and is what Safari on Catalina uses for HTTPS connections. The older TLSv1.2 is also supported.

Is there a particular issue or error or diagnostic or concern here? If so, what's the text of the message or diagnostic?

If some website is telling you that you need TLS, you have that.

Which implies there's something odd happening here if you're receiving an error from a Safari HTTPS connection into the website, if that's what you're doing.

You are likely navigating to the site using http instead of https.