If you can get a valuation of €225k or above, you will be eligible for Avant's 2.15% rates, which you can fix for up to 7 years.
If you switch to that 2.15% rate, you will save €180,000*(3.8-2.15)/100 = €2,970 in interest per year.
There will be solicitors', valuation and break fees of about €(1,300 + 185 + 1,900) = €3,385 but that is a one-off cost, and Avant will pay you €1,500 to switch (provided you use a broker who is an Avant "Gold Partner").
If you get a valuation that is a little below €225k and you have some spare cash, you can overpay your KBC mortgage (probably without penalty) to bring your LTV below 80%. E.g., if you get a valuation of €220k, you will need to reduce your mortgage balance to €176k to be eligible for Avant's 2.15% rates.