You've asked the right man. I swear by braces; I'm the youngest person to wear them in the country, probably.
Always, always, always get BUTTON braces. Clip-on braves are as classless as clip-on neckties. It's not difficult attaching the requisite buttons to your trousers yourself, but if you really can't manage, you have someone to do it for you. The buttons need to be attached so that the braves form a perpendicular line with the waist of your trousers - with the ground, ultimately.
A belt can be obtained that will continue to for you through weight loss; you just need to get a large enough belt and start with the largest fitting, going down. But braces look a lot better and more sophisticated, as well as being more comfortable and easier to work around weight changes.
You can wear braces with t-shirts, but you'd be better off with real shirts.
These are similar to the pair I have:
https://www.amazon.co.uk/Clermont-Direc ... ay&sr=8-16
But as long as you're willing to spend £20 or more, you'll be alright.