When I'm looking for a good bar, music tends to enter the equation. When in Ireland, I mean genuine "sessions" as opposed to lots of sing along "bar music". In Scotland, we've found fewer sessions, but it still guides my choices of bars and what towns I decide to stay in. I use https://thesession.org/sessions and Facebook.
At MacGregors in Inverness, we sat amongst at least 20 locals participating in a genuine session, including an 11 year old prodigy on the fiddle.
We spent three nights in Portree a few years ago and after seeing a sign for "trad music" for a different bar each night, and struggling for a good seat, we saw the same two musicians all three nights. Although they were good musicians, we get tired of Dirty Old Town and pop covers, so we left during setup the second and third nights.
Way back in 1997, we stayed in a hostel in Glasgow and on the desk clerks advice went to a nearby bar that was huge, loud, pop music, and everyone but us was drinking Bud Light. We got odd looks for ordering Guinness. It was "popular with locals" but not for us.