I think the Crown is enmeshed in UK consitutional law to an extent that it would require quite a lot of patient work to unpick and replace it, but again, the "aren't you ashamed of yourself?" riposte applies, given that the argument for keeping the monarchy is essentially "can't be arsed doing anything else".

My personal least favourite argument is "they've been trained for this all their lives", to which I think Charles himself stands as adequate response. 75 years of training and he is bad at this.

Ireland's presidency is an odd one - we've had very decent run over the years, which either speaks to a systemic elegance (which isn't entirely visible in the composition of the Oireachtas, God bless it) or blind good luck. Some of our presidents have been better poets than the incumbent, including the ones who weren't poets...