Surgery and concert clash- Looking for Liverpool tickets

Hi all, feeling quite deflated at the moment as have tickets for the Manchester gig which I've been super excited for as I've never seen her live before, but have found out this week that I'm having major surgery the day before the Manchester date. I'm hoping to instead find tickets for a UK show before this surgery (Liverpool is ideal but could potentially travel further).

I've never bought resell tickets before so was wondering if anyone had any thoughts on best websites to use and not get scammed on for this? Ticketmaster isn't really showing anything at the moment (apart from £300 per ticket). Looking for 2 so my partner can support. Thank you in advance for any advice.