Hi Robbie,
The SY Control Tower is undergoing maintenance and refurbs.
Separate to that, the construction you see airside, nearby, is the completion of works involving the upgrading of the Kilo Apron bays in the South East sector to 5 remote hard-stands.
Inground fuel-lines, pre-conditioned air and ground power is being implemented on all 5 bays.
Currently Bays 124 and 125 are complete. Works are continuing on bays 120, 121 and 122. Works estimated completion early 2025.
Taxiway Juliet is also being extended across 34L/16R from the east side of the airport to the West side. All taxiway works are being completed during curfew hours.
Update 1
https://www.youtube.com/watch?v=BFZaohBBq2M
Update 2
https://www.youtube.com/watch?v=MHOa96U1jf0