The 3.5 GHz bands have been allocated in the Netherlands Dutch
The outcome of the bidding round can be found here: https://open.overheid.nl/documenten/6733d919-3a39-4416-8fc7-52a9e12d7ba7/file
VodafoneZiggo gets 3450 – 3550 MHz
T-Mobile Odido gets 3550 – 3650 MHz
KPN gets 3650 – 3750 MHz
Many antenna towers are already equipped with 3.5 GHz hardware, so 3.5 GHz 5G should be broadly available soon.
This map has some information about the 3.5 GHz capabilities of many of the towers: https://antennekaart.nl/kaart