Covid can be scary alright for people. In dentistry we are well used to avoiding contagious diseases spreading between patient and between the staff and patients. A coronavirus is nothing new, and very easy to kill.
Generally dentist are instigating social distancing and ensuring that patient know not to attend if they have any risk of covid infection. Its that last bit is the important bit because if the last patient didn't have covid then there is not risk.
Before Covid, after each patient the nurse would clean the room down, disinfect the surfaces and move the old instruments and put out new sterile ones. In the covid world them same is done, except Covid is much easier to kill that most of the nasty's that dentist are concerned with.
The main thing is that you are well. You attend alone, you get in and out as fast as possible, dont be brushing your teeth in the bathroom, infact if you can use your own bathroom at home before you leave all the better. The dentist will be in full PPE depending on their risk not yours. The dirtiest thing in the surgery will be you unfortunately and you have come in from outside bringing the outside with you, the dentist surgery is a very controllable environment otherwise.
Stress not, dentistry represents no great risk. Dentists are on the ball from decades of practice with PPE and cross infection control and generally wont get all worked up about it. The dentist is the one taking most of the risk here not you, so be cognisant of this when making demands.