I currently bank with AIB and it seems like there is an issue with 5 year fixed rate with overpayments but maybe it's not important if it's only 10 year mortgage ?
There is a quirk with AIB's 5-year fixed rate that means that you will be able to make unlimited overpayments without penalty for the foreseeable future.
I've had a look at brokers comparisons site but should I still apply for as many AIPs as possible ?
Get AIP from at least two lenders – maybe more. Rates could easily rise before you draw down.
You only need a broker if you want a mortgage from Avant or Haven. But note that Haven are very slow, at least for people who are switching their mortgage.
Here are the rates you are eligible for. (Ignore the rates marked ">€250k".) Since you planning to overpay, I would lean towards 4- or 5-year fixed rates. BOI and PTSB offer cashback on some of their rates. (So do EBS on their non-green rates, but they are slow at the moment.) Note that
AIB's rates are slightly lower than the ones shown in this table if your LTV is 50% or less.
You could try to get a €250k mortgage in order to be eligible for the lower rates
That would put you into a higher LTV bracket, so you'd need to look at
a different rates table. PTSB (but not BOI) will still give you cashback. Then you could make a lump-sum overpayment shortly after you draw down (assuming the break fee is modest).