What next?

You need the tweeters to play the full range, it will sound odd with them disconnected. Either EQ settings need attention (you could try a custom one based on a preset you're using and turn down the high end.) Or the tweeters are bust, but I think they are generally more robust than the mid range ones. The tweeters are high up because of how human hearing works. Higher frequencies sort of "place" the sounds. Also best to ensure any "loud" setting on the HU is turned to off. This setting is designed to make music sound louder at lower volumes, and does so by boosting the bass and treble.

If replacing speakers best type for the fronts are components with the tweeters preferably in the factory location. Only limitation on front speakers is mounting depth, which needs to be clear of the window rail thingy inside the door.