The most official bridge is matrix-appservice-irc which seemed fine from a user perspective, but Libera kicked out the official matrix.org bridge because it caused problems at scale. They didn't ban use of matrix-appservice-irc so probably still the way to go.

In https://libera.chat/guides/matrix#can-i-run-my-own-matrix-bridge:

Different bridging software may use different terminology or have different functionality. Regardless of the software, we recommend the following:

• Do choose a single IRC puppet instead of 1:1 bridging if possible, especially if the channel is a matrix-first community
• Do allow bridging between consenting matrix rooms and IRC channels
• Do not allow your bridge to join users to IRC channels without consent from channel owners
• Do not allow your bridge to direct message arbitrary IRC users

https://github.com/matrix-org/matrix-appservice-irc?tab=readme-ov-file#what-does-it-do

Each real Matrix user is represented by an IRC client, and each real IRC client is represented by a Matrix user.

matrix-appservice-irc is a 1:1 bridge that would break the recommended "single IRC puppet" recommendation upstream.

It should be relatively easy to setup https://wikitech.wikimedia.org/wiki/Tool:Bridgebot to join a local Matrix homeserver with specific #wikimedia-/#mediawiki- IRC channels. The bot currently operates a bridge between the #wikimedia-rust libera.chat IRC channel and the #wikimedia-rust:matrix.org room.