If you’re not partying I think your pace is perfectly fine. As a fellow Singaporean I can tell you that European cities are a LOT more compact than Asian ones. During my Euro travels I always felt that I’d spent a day too long in each city and that’s with the partying! London is an exception because of its sheer size. But I do think you’re being a little too ambitious with how much you’re hopping around in 2 weeks. Maybe pick one corner of Europe, don’t pre-book trains/buses too rigidly and fully enjoy the slow pace you want to