I have six cams behind glass. None of them doing LPR duty. Three of them are in upstairs windows with black cloth behind them, between the cam and the blinds and curtains. They do well with very little to no reflections on the glass. These are used for wide angle overviews and stay in color 24/7. Depending on the time of year and time of day, there can be some sun glare for 20-30 minutes when the sun is directly on the window.
The other three are cams at my front door behind the glass side windows. They work well in daylight but do have some issues with reflected glare at night due to the light-colored shear curtains hung behind them. These also stay in color 24/7.
Here is an example of one of the three upstairs window cams. It is mounted on a board in the window behind the blinds. Normally the curtains are pulled across the blinds but I have pulled them back for reference.
Here is an example of one of the three front door cams. Note the shear curtains which do not give adequate blocking of light from inside.
Hope this helps.