The OP has a 20 year timeline so an illiquid asset might be very suitable.
It does not matter how long there period is, if you need to get out and can't it's illiquid. And there were plenty of people who got caught out this way in the last recession.
The OP has €120k available and is talking about investing €120k. I do not see any reference to borrowing.
You obviously missed this statement:
The other alternative is use the 120k. Buy a property in Dublin for 350 to 400k ish.
After all why diversify if you can identify the best opportunity.
Because there are very very few investors that are that good. Every thing we have seen from the OP would suggest he is not in that league.
However I do admire his approach, and to dismiss it based on generalities shows little respect.
The reason that so many Irish investors got wipe out in the last crash was because they ignored those very generalities. People can blame it on the banks, the economy etc... but the reality is that had they not ignored those generalities as you call them they would not have been in a position where they would have had to take that hit in the first place. I see nothing to respect in repeating the failures of the past.