Just in case some additional information helps. My XPS 13 9365 has a High DPI touchscreen and the icons look very similar in Spyder 5.3.0. The DPI is 3200 x 1800 and it uses 200 % Scaling and Layout by default. If an external monitor is attached with a standard resolution of 1920 x 1080 and 100 % scaling it displays as expected.
My guess would be changing the Windows Display Scaling from 100 % to 200 % should make the icons look twice as large as it does in most applications. In the case of Spyder, the icons stay the same size and therefore look very small.