It’s not so easy to challenge landlords (who are probably pension funds, investment trusts, private equity groups and other financial institutions based elsewhere, if not outside the UK) who work through property management companies who are also based elsewhere when the council has little power to actually force such landlords to change their behaviour. Any losses in Wrexham can be put against profits made elsewhere. Business rates are set nationally. Compulsory purchase is hardly an option these days. Probably the only landlord in the town, apart from private individuals e.g. the proprietors of the Fat Boar, Lot 11, the Bank and one or two others, to actually look after and invest in their property is the council. You need to redirect your fire elsewhere.
When there was more money about at least the council used to power wash the streets every year or so, but the age of austerity has seen that confined to the history books sadly because it has to come out of everyday spending i.e. council tax along with schools, social services,refuse collection etc etc and you won’t get any help from the welsh government for that.