Safari - Find a Specific Tab and Open It - If it Doesn't Exist then Open a New Tab

Don't assume – test...

Make damn sure Arc is scriptable before doing anything.

If it is then you can go-to-town.

Here's a place to start:

Checking Whether a Given URL is Already Open in Google Chrome Tabs - #2 by peternlewis

There are a number of other macros on the forum that do this kind of thing.

Here's one:

Google Chrome – How to Bring an Existing GMail Tab to the Front - #11 by ccstone