Lichess allows you to upload a custom bots and play them (and other can too), and I believe you can also run against other bots. There's also https://www.chess.

Lichess allows you to upload a custom bots and play them (and other can too), and I believe you can also run against other bots. There's also https://www.chess.com/computer-chess-championship https://www.chess.com/computer-chess-championship, but IDK how one enters.