Welcome to the forums!
You have certainly come to the right place as you will find all you need to know on budgie care here.
Since you are relatively new to budgies, the information on the several articles and sticky threads located at the top part of each section of the forums will be extremely useful as you become reacquainted with the species.
From your description, it seems your budgie is still in the process of getting used to his new home and family. You can facilitate the process by covering the cage on 3 sides and having some music or background sound from the radio or TV.
It's also perfectly normal for a new budgie to not feel confident enough to play with the toys. Some budgies don't even know what toys are for and when it comes to this, we can also help them out in terms of encouraging them to investigate the toys.
In case you don't know, budgies can screech when happy/excited, this is not exclusively related to a negative feeling comig from your budgie, it can also happen as a response when feeling overly enthusiastic.
As you become more familiar in reading and interpreting behaviour and body language, it will be easier to tell the differences in your budgie's singing.
Since your budgie is currently so scared of you, when approaching the cage to clean or change food or water it's best for you to avoid sudden movements and act as if you are in slow motion.
Having some soothing music on will also be helpful in terms of reducing your budgie's stress levels and making him feel more relaxed.
In terms of bonding, the very first step is to make the initial connection and establish the foundations of trust and this is done by sitting close to the cage and talking to your budgie in a calm, positive, encouraging and reassuring way. By doing this, your budgie will increasingly get used to your voice/presence and with time will realize your are not a threat.
Once he shows receptiveness and curiosity towards you (by coming closer to you while in the cage), then you can take the next step by slowly introducing your hand and offering him a little treat to eat.
For all the detailed information, be sure to check the stickies here at the Taming and Bonding section.
This link may be of use: https://talkbudgies.com/taming-bondin...id-people.html
Best of luck with your new budgie friend!