not may active members here from Ireland as far as i am aware ( i am in the UK )
i did see this link which mentions IV abx
https://d2medical.ie/services/lyme-disease/ but i have no experience of them
however from my reading around the subject - its seems as though the evidence for greater efficacy with IV abx vs oral abx is limited - and as a result due to the increased risk to the patient its usually reserved for urgent life threatening cases - eg severe lyme meningitis, lyme carditis - or optical complications that threaten loss of sight.
IV abx certainly do reach higher concentrations than oral - but the main issue is that once lyme has become chronic - by around 6montsh or so - the lyme bacteria are existing in biofilms colonies and have changed phenotype to one which is no longer very susceptible to abx in any concentration - hence the high failure rate in both Oral and IV regimes.
successful regimes in chronic cases seem to be long term - that gradually wear the infection down - rather than short sharp shock
i wish you luck in whichever path you choose