@Laxeros the Kelvingrove Art Gallery is always good for a visit, so is the Burrell Collection (and you will need indoor things in case the weather is terrible). Kelvingrove park next to the museum is nice (also the University is there for a wander round), and you can walk quite a way out of town on the Kelvin walkway by the river. By the University is Byres road, the main shopping area of the West End (not sure how exciting that is really, because to me those are the local shops; but the lanes - Ashton Lane, Cresswell Lane, Ruthven Lane - are definitely tourist-worthy oddities

In the other direction down by the Clyde there's the Transport museum; not the best of these but a nice building (by Zaha Hadid), with the Tall Ship beside it and footbridges across the river. You mention street art: there's a mural trail in the town centre https://www.citycentremuraltrail.co.uk/ GOMA in town has some nice modern art stuff too.

Hillwalking - is mostly done elsewhere, by taking a train up to Loch Lomond (Balloch), which is pretty nice tho will be COLD that time of year; there's some nice smaller hills for a walk or fell run closer to hand at Old Kilpatrick https://www.walkhighlands.co.uk/glasgow/duncolm.shtml but quite boggy, better in the summer. If you are into hills, the climbing wall in govan (in an old church) may appeal?

Restaurant wise, Mother India is a perennial favourite for curries https://www.motherindia.co.uk/mother-india/ and the next street closer to the river there is the Finnieston area, has become gentrified with a lot of nice restaurants. Down a lane there is the Hidden Lane, quirky shops https://www.thehiddenlaneglasgow.com/

At that time you're probably best getting around using the tube, but if you get back in the summer, there's hire bikes. There's a double decker tourist bus does circuits, apparently you can get a hop on/off ticket but I've never done that as I live here!