how to duplicate display with differant resolution on monitors. when I select this option, my laptop changes to second monitor size
Windows duplicate mode does exactly that - clones your screen including the resolution. Extended mode uses the recommended resolution for each of your monitors separately, and you’d be able to set different resolutions between your main and secondary monitors manually. Would extended mode be an option? Another possibility depending on your need is to set your display settings to Projector Only mode via your computer (usually Function-F5 on laptops). This would disable your main monitor and only display on your secondary monitor, which would allow the second monitor to use its optimal resolution.
Another option to consider is DisplayLink’s Multiple Monitor software. I don’t believe it offers multiple resolutions while in duplicate mode but would offer some other solutions to avoid using duplicate mode.
There is a 30 day free trial so you could play around with it and see if it would meet your needs:
Hope this helps!