Yes, actually, I noticed the same things with my lo back at that age. We found that those dangly toys are inescapable for a baby that young, so it may be best to only have one hanging at a time, and then switch it out to keep their interest. This way they can get a variety of things to look at, but not get overwhelmed by multiple things at the same time. Also consider how long you let your lo sit there, I would limit it to a pretty short time period. (Sorry, I already forgot what the awake periods are like for a baby that age, but I would keep it to maybe 15-20% at the most, but watch your lo's cues).
For calming activities you may like using a baby carrier (or just carry them in your arms) for about 20 minutes before you'd like to put them in bed. They can still look around, but the motion is calming. (Unless doing it for that long puts them to sleep, and then I would do it for less time). You could sing to them while they lay on their back, do a few calm action songs baby to keep them interested without getting overly excited. You could also read books with them over the shoulder so that they don't get worked up over the illustrations, but enjoy listening to your voice. You could also get some soft stuffed animals and other textural toys and rub them on your lo's arms, and face to give them a chance have sensory experiences without working to hard. A slow dance close to end of the awake period is nice for both mummy and baby, and that will help prep. them for naptime. Tummy time may be good too, some babies love it and can lay peacefully when they get tired - although some babies find it uncomfortable. I would just experiment and see how your baby reacts to some of these or any others you come up with and see which activities are the most stimulating, and do those first, and then change each activity to progress towards the most calming. It takes a bit more work to organize their awake periods into little chunks like that, but the result of longer naps, and a more rested child is worth it in my opinion.
Hope that helps!