How can I put new types of controls in the filters of my views? I mean, more modern fields beyond the basics, for example, number sliders, selects with checkboxes inside, among others?
Yes this is possible to do however it would require some amount of css and html knowledge in order to achieve as these are not standard features of our plugins.
Our filters are generally rendered with the default styling of your theme and browser.
Unfortunately no, we load the bootstrap css styling, its really up to the customer to customize the styling how they see it fit. This is because the bootstrap framework doesn't provide any such customizations. Users will need to manipulate the bootstrap css to fit their specific needs.